1.  Covered with, or containing, extraneous matter which is injurious, noxious, offensive, or obstructive; filthy; dirty; not clean; polluted; nasty; defiled; as, a foul cloth; foul hands; a foul chimney; foul air; a ship's bottom is foul when overgrown with barnacles; a gun becomes foul from repeated firing; a well is foul with polluted water. [1913 Webster]
"My face is foul with weeping." [1913 Webster]

2.  Scurrilous; obscene or profane; abusive; as, foul words; foul language. [1913 Webster]

3.  Hateful; detestable; shameful; odious; wretched. Shak. [1913 Webster]
"Who first seduced them to that foul revolt?" [1913 Webster]

4.  Loathsome; disgusting; as, a foul disease. [1913 Webster]

5.  Ugly; homely; poor. Chaucer. [1913 Webster]
"Let us, like merchants, show our foulest wares." [1913 Webster]

6.  Not favorable; unpropitious; not fair or advantageous; as, a foul wind; a foul road; cloudy or rainy; stormy; not fair; -- said of the weather, sky, etc. [1913 Webster]
"So foul a sky clears not without a storm." [1913 Webster]

7.  Not conformed to the established rules and customs of a game, conflict, test, etc.; unfair; dishonest; dishonorable; cheating; as, foul play. [1913 Webster]

8.  Having freedom of motion interfered with by collision or entanglement; entangled; -- opposed to clear; as, a rope or cable may get foul while paying it out. [1913 Webster]

1.  To make filthy; to defile; to daub; to dirty; to soil; as, to foul the face or hands with mire. [1913 Webster]

2.  To incrust (the bore of a gun) with burnt powder in the process of firing. [1913 Webster]

3.  To cover (a ship's bottom) with anything that impered its sailing; as, a bottom fouled with barnacles. [1913 Webster]

4.  To entangle, so as to impede motion; as, to foul a rope or cable in paying it out; to come into collision with; as, one boat fouled the other in a race. [1913 Webster]

1.  To become clogged with burnt powder in the process of firing, as a gun. [1913 Webster]

2.  To become entagled, as ropes; to come into collision with something; as, the two boats fouled. [1913 Webster]

1.  An entanglement; a collision, as in a boat race. [1913 Webster]

2.  See Foul ball, under Foul, a. [1913 Webster]

3.  In various games or sports, an act done contrary to the rules; a foul stroke, hit, play, or the like. [Webster 1913 Suppl.]

foul, adj., n., adv., & v.
--adj.
1 offensive to the senses; loathsome, stinking.
2 dirty, soiled, filthy.
3 colloq. revolting, disgusting.
4 a containing or charged with noxious matter (foul air). b clogged, choked.
5 morally polluted; disgustingly abusive or offensive (foul language; foul deeds).
6 unfair; against the rules of a game etc. (by fair means or foul).
7 (of the weather) wet, rough, stormy.
8 (of a rope etc.) entangled.
9 (of a ship's bottom) overgrown with weeds, barnacles, etc.
--n.
1 Sport an unfair or invalid stroke or piece of play.
2 a collision or entanglement, esp. in riding, rowing, or running.
3 a foul thing.
--adv. unfairly; contrary to the rules.
--v.
1 tr. & intr. make or become foul or dirty.
2 tr. (of an animal) make dirty with excrement.
3 a tr. Sport commit a foul against (a player). b intr. commit a foul.
4 a tr. (often foll. by up) cause (an anchor, cable, etc.) to become entangled or muddled. b intr. become entangled.
5 tr. jam or block (a crossing, railway line, or traffic).
6 tr. (usu. foll. by up) colloq. spoil or bungle.
7 tr. run foul of; collide with.
8 tr. pollute with guilt; dishonour.

Idiom:
foul brood a fatal disease of larval bees caused by bacteria. foul mouth a person who uses foul language. foul play
1 unfair play in games.
2 treacherous or violent activity, esp. murder. foul-up a muddled or bungled situation.

Derivative:
foully adv. foulness n.

Etymology:
OE ful f. Gmc

N  badness, hurtfulness, virulence, evil doer, bane, plague spot, evil star, ill wind, hoodoo, Jonah, snake in the grass, skeleton in the closet, amari aliquid, thorn in the side, malignity, malevolence, tender mercies, ill-treatment, annoyance, molestation, abuse, oppression, persecution, outrage, misusage, injury, knockout drops, badness, peccancy, abomination, painfulness, pestilence, guilt, depravity, hurtful, harmful, scathful, baneful, baleful, injurious, deleterious, detrimental, noxious, pernicious, mischievous, full of mischief, mischief-making, malefic, malignant, nocuous, noisome, prejudicial, disserviceable, disadvantageous, wide-wasting, unlucky, sinister, obnoxious, untoward, disastrous, oppressive, burdensome, onerous, malign, corrupting &c (corrupt), virulent, venomous, envenomed, corrosive, poisonous, deadly, destructive, inauspicious, bad, ill, arrant, as bad as bad can be, dreadful, horrid, horrible, dire, rank, peccant, foul, fulsome, rotten, rotten at the core, vile, base, villainous, mean, injured, deteriorated, unsatisfactory, exceptionable indifferent, below par, illcontrived, ill-conditioned, wretched, sad, grievous, deplorable, lamentable, pitiful, pitiable, woeful, evil, wrong, depraved, shocking, reprehensible, hateful, hateful as a toad, abominable, detestable, execrable, cursed, accursed, confounded, damned, damnable, infernal, diabolic, unadvisable, unprofitable, incompetent, irremediable, badly, wrong, ill, to one's cost, where the shoe pinches, bad is the best: the worst come to the worst, herba mala presto cresco, wrongs unredressed or insults unavenged.

N  uncleanness, impurity, immundity, immundicity, impurity, defilement, contamination, defoedation, soilure, soiliness, abomination, leaven, taint, tainture, fetor, decay, putrescence, putrefaction, corruption, mold, must, mildew, dry rot, mucor, rubigo, slovenry, slovenliness, squalor, dowdy, drab, slut, malkin, slattern, sloven, slammerkin, slammock, slummock, scrub, draggle-tail, mudlark, dust-man, sweep, beast, dirt, filth, soil, slop, dust, cobweb, flue, smoke, soot, smudge, smut, grit, grime, raff, sossle, sozzle, sordes, dregs, grounds, lees, argol, sediment, settlement heeltap, dross, drossiness, mother, precipitate, scoriae, ashes, cinders, recrement, slag, scum, froth, hogwash, ditchwater, dishwater, bilgewater, rinsings, cheeseparings, sweepings, offscourings, outscourings, off scum, caput mortuum, residuum, sprue, fecula, clinker, draff, scurf, scurfiness, exuviae, morphea, fur, furfur, dandruff, tartar, riffraff, vermin, louse, flea, bug, chinch, mud, mire, quagmire, alluvium, silt, sludge, slime, slush, slosh, sposh, spawn, offal, gurry, lientery, garbage, carrion, excreta, slough, peccant humor, pus, matter, suppuration, lienteria, faeces, feces, excrement, ordure, dung, crap, shit, sewage, sewerage, muck, coprolite, guano, manure, compost, dunghill, colluvies, mixen, midden, bog, laystall, sink, privy, jakes, toilet, john, head, cess, cesspool, sump, sough, cloaca, latrines, drain, sewer, common sewer, Cloacina, dust hole, sty, pigsty, lair, den, Augean stable, sink of corruption, slum, rookery, dirty, filthy, grimy, unclean, impure, soiled, not to be handled with kid gloves, dusty, snuffy, smutty, sooty, smoky, thick, turbid, dreggy, slimy, mussy, slovenly, untidy, messy, uncleanly, unkempt, sluttish, dowdy, draggle-tailed, uncombed, unscoured, unswept, unwiped, unwashed, unstrained, unpurified, squalid, lutose, slammocky, slummocky, sozzly, nasty, coarse, foul, offensive, abominable, beastly, reeky, reechy, fetid, decayed, moldy, musty, mildewed, rusty, moth-eaten, mucid, rancid, weak, bad, gone bad, etercoral, lentiginous, touched, fusty, effete, reasty, rotten, corrupt, tainted, high, flyblown, maggoty, putrid, putrefactive, putrescent, putrefied, saprogenic, saprogenous, purulent, carious, peccant, fecal, feculent, stercoraceous, excrementitious, scurfy, scurvy, impetiginous, gory, bloody, rotting, rotten as a pear, rotten as cheese, crapulous, gross, fimetarious, fimicolous, they that touch pitch will be defiled.

N  ugliness, deformity, inelegance, acomia, disfigurement, want of symmetry, inconcinnity, distortion, squalor, forbidding countenance, vinegar aspect, hanging look, wry face, spretae injuria formae, eyesore, object, witch, hag, figure, sight, fright, monster, dog, woofer, pig, octopus, specter, scarecrow, harridan, satyr, toad, monkey, baboon, Caliban, Aesop, monstrum horrendum informe ingens cui lumen adempt, ugly, ugly as sin, ugly as a toad, ugly as a scarecrow, ugly as a dead monkey, plain, bald (unadorned), homely, ordinary, unornamental, inartistic, unsightly, unseemly, uncomely, unlovely, unshapely, sightless, seemless, not fit to be seen, unbeauteous, unbeautiful, beautiless, semibeautiful, shapeless, misshapen, misproportioned, monstrous, gaunt, dumpy, curtailed of its fair proportions, ill-made, ill- shaped, ill-proportioned, crooked, hard featured, hard visaged, ill-favored, hard-favored, evil-favored, ill-looking, unprepossessing, unattractive, uninviting, unpleasing, graceless, inelegant, ungraceful, ungainly, uncouth, stiff, rugged, rough, gross, rude, awkward, clumsy, slouching, rickety, gawky, lumping, lumpish, lumbering, hulky, hulking, unwieldy, squalid, haggard, grim, grim faced, grim visaged, grisly, ghastly, ghost like, death like, cadaverous, grewsome, gruesome, frightful, hideous, odious, uncanny, forbidding, repellant, repulsive, repugnant, grotesque, bizarre, grody, grody to the max, horrid, horrible, shocking, foul, dingy, gaudy, disfigured, discolored.

VB  flash on the mind, say what comes uppermost, improvise, extemporize, give an impetus, impel, push, start, give a start to, set going, drive, urge, boom, thrust, prod, foin, cant, elbow, shoulder, jostle, justle, hustle, hurtle, shove, jog, jolt, encounter, run against, bump against, butt against, knock one's head against, run one's head against, impinge, boost, bunt, carom, clip y, fan, fan out, jab, plug, strike, knock, hit, tap, rap, slap, flap, dab, pat, thump, beat, blow, bang, slam, dash, punch, thwack, whack, hit hard, strike hard, swap, batter, dowse, baste, pelt, patter, buffet, belabor, fetch one a blow, poke at, pink, lunge, yerk, kick, calcitrate, butt, strike at, whip, come into a collision, enter into collision, collide, sideswipe, foul, fall foul of, run foul of, telescope, throw.

N  improbity, dishonesty, dishonor, deviation from rectitude, disgrace, fraud, lying, bad faith, Punic faith, mala fides, Punica fides, infidelity, faithlessness, Judas kiss, betrayal, breach of promise, breach of trust, breach of faith, prodition, disloyalty, treason, high treason, apostasy, nonobservance, shabbiness, villainy, villany, baseness, abjection, debasement, turpitude, moral turpitude, laxity, trimming, shuffling, perfidy, perfidiousness, treachery, double dealing, unfairness, knavery, roguery, rascality, foul play, jobbing, jobbery, graft, bribery, venality, nepotism, corruption, job, shuffle, fishy transaction, barratry, sharp practice, heads I win tails you lose, mouth honor, dishonest, dishonorable, unconscientious, unscrupulous, fraudulent, knavish, disgraceful, wicked, false-hearted, disingenuous, unfair, one-sided, double, double- hearted, double-tongued, double-faced, timeserving, crooked, tortuous, insidious, Machiavelian, dark, slippery, fishy, perfidious, treacherous, perjured, infamous, arrant, foul, base, vile, ignominious, blackguard, contemptible, unrespectable, abject, mean, shabby, little, paltry, dirty, scurvy, scabby, sneaking, groveling, scrubby, rascally, pettifogging, beneath one, low-minded, low-thoughted, base-minded, undignified, indign, unbecoming, unbeseeming, unbefitting, derogatory, degrading, infra dignitatem, beneath one's dignity, ungentlemanly, ungentlemanlike, unknightly, unchivalric, unmanly, unhandsome, recreant, inglorious, corrupt, venal, debased, mongrel, faithless, of bad faith, false, unfaithful, disloyal, untrustworthy, trustless, trothless, lost to shame, dead to honor, barratrous, dishonestly, mala fide, like a thief in the night, by crooked paths, Int, O tempora!, O mores!, corruptissima respublica plurimae leges.

N  vice, evil-doing, evil courses, wrongdoing, wickedness, viciousness, iniquity, peccability, demerit, sin, Adam, old Adam, offending Adam, immorality, impropriety, indecorum, scandal, laxity, looseness of morals, enphagy, dophagy, exophagy, want of principle, want of ballast, obliquity, backsliding, infamy, demoralization, pravity, depravity, pollution, hardness of heart, brutality, corruption, knavery, profligacy, flagrancy, atrocity, cannibalism, lesbianism, Sadism, infirmity, weakness, weakness of the flesh, frailty, imperfection, error, weak side, foible, failing, failure, crying sin, besetting sin, defect, deficiency, cloven foot, lowest dregs of vice, sink of iniquity, Alsatian den, gusto picaresco, fault, crime, criminality, sinner, brothel, gambling house, joint, opium den, shooting gallery, crack house, vicious, sinful, sinning, wicked, iniquitous, immoral, unrighteous, wrong, criminal, naughty, incorrect, unduteous, undutiful, unprincipled, lawless, disorderly, contra bonos mores, indecorous, unseemly, improper, dissolute, profligate, scampish, unworthy, worthless, desertless, disgraceful, recreant, reprehensible, blameworthy, uncommendable, discreditable, disreputable, Sadistic, base, sinister, scurvy, foul, gross, vile, black, grave, facinorous, felonious, nefarious, shameful, scandalous, infamous, villainous, of a deep dye, heinous, flagrant, flagitious, atrocious, incarnate, accursed, Mephistophelian, satanic, diabolic, hellish, infernal, stygian, fiendlike, hell-born, demoniacal, devilish, fiendish, miscreated, misbegotten, demoralized, corrupt, depraved, evil-minded, evil-disposed, ill-conditioned, malevolent, heartless, graceless, shameless, virtueless, abandoned, lost to virtue, unconscionable, sunk in iniquity, lost in iniquity, steeped in iniquity, incorrigible, irreclaimable, obdurate, reprobate, past praying for, culpable, reprehensible, unjustifiable, indefensible, inexcusable, inexpiable, unpardonable, irremissible, weak, frail, lax, infirm, imperfect, indiscrete, demoralizing, degrading, wrong, sinfully, without excuse, Int, O tempora!, O mores!, alitur vitium vivitque tegendo, genus est mortis male vivere, mala mens malus animus, nemo repente fuit turpissimus, the trail of the serpent is over them all, to sanction vice and hunt decorum down.

N  odor, smell, odorament, scent, effluvium, emanation, exhalation, fume, essence, trail, nidor, redolence, sense of smell, scent, act of smelling, olfaction, olfactories, fragrance, odorant, bloodhound, hound, spoor, odorous, odoriferous, smelling, reeking, foul-smelling, strong- scented, redolent, graveolent, nidorous, pungent, putrid, foul, olfactory, quick-scented.

foul ball, foul language, foul line, foul matter, foul mouthed, foul out, foul play, foul shot, foul tongued, foul up, personal foul, technical foul