1.  unclean(a = adj.all) dirty, soiled - soiled or likely to soil with dirt or grime; "a child in dirty overalls"; "Cinderella did the dirty work while her sisters preened themselves"; "dirty slums"; "dirty unswept sidewalks"; "mining is a dirty job"; "piles of dirty dishes"; "put his dirty feet on the clean sheet"; "wore an unclean shirt"
Derived form noun uncleanness₁

2.  unclean(a = adj.all) impure - having a physical or moral blemish so as to make impure according to dietary or ceremonial laws; "and the swine...is unclean to you"; "unclean meat"
Antonym: clean
Derived form noun uncleanness₁

1.  Not clean; foul; dirty; filthy. [1913 Webster]

2.  Ceremonially impure; needing ritual cleansing. [1913 Webster]

3.  Morally impure. Perkins. [1913 Webster]

unclean, adj.
1 not clean.
2 unchaste.
3 unfit to be eaten; ceremonially impure.
4 Bibl. (of a spirit) wicked.

Derivative:
uncleanly adv. uncleanly adj. uncleanliness n. uncleanness n.

Etymology:
OE uncl{aelig}ne (as UN-(1), CLEAN)

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  impurity, uncleanness, immodesty, grossness, indelicacy, indecency, impudicity, obscenity, ribaldry, Fescennine, smut, bawdry, double entente, equivoque, concupiscence, lust, carnality, flesh, salacity, pruriency, lechery, lasciviency, lubricity, Sadism, sapphism, incontinence, intrigue, faux pas, amour, amourette, gallantry, debauchery, libertinish, libertinage, fornication, liaison, wenching, venery, dissipation, seduction, defloration, defilement, abuse, violation, rape, incest, prostitution, social evil, harlotry, stupration, whoredom, concubinage, cuckoldom, adultery, advoutry, crim, con, free love, seraglio, harem, brothel, bagnio, stew, bawdyhouse, cat house, lupanar, house of ill fame, bordel, bordello, impure, unclean, not to be mentioned to ears polite, immodest, shameless, indecorous, indelicate, indecent, Fescennine, loose, risque, coarse, gross, broad, free, equivocal, smutty, fulsome, ribald, obscene, bawdy, pornographic, concupiscent, prurient, lickerish, rampant, lustful, carnal, carnal-minded, lewd, lascivious, lecherous, libidinous, erotic, ruttish, salacious, Paphian, voluptuous, goatish, must, musty, unchaste, light, wanton, licentious, debauched, dissolute, of loose character, of easy virtue, frail, gay, riggish, incontinent, meretricious, rakish, gallant, dissipated, no better than she should be, on the town, on the streets, on the pave, on the loose, adulterous, incestuous, bestial.