1.  foil(n = noun.artifact) - a piece of thin and flexible sheet metal; "the photographic film was wrapped in foil"
is a kind of sheet metal
has particulars: aluminium foil, aluminum foil, tin foil, chaff, gold foil, tin foil, tinfoil
Derived forms verb foil₃, verb foliate₃, verb foliate₁

2.  foil(n = noun.cognition) enhancer - anything that serves by contrast to call attention to another thing's good qualities; "pretty girls like plain friends as foils"
is a kind of attention
Derived form verb foil₁

3.  foil(n = noun.artifact) hydrofoil - a device consisting of a flat or curved piece (as a metal plate) so that its surface reacts to the water it is passing through; "the fins of a fish act as hydrofoils"
is a kind of device

4.  foil(n = noun.artifact) transparency - picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector;
is a kind of icon, ikon, image, picture
has particulars: lantern slide, slide, overhead, viewgraph

5.  foil(n = noun.artifact) - a light slender flexible sword tipped by a button;
is a kind of fencing sword

1.  foil(v = verb.stative) - enhance by contrast; "In this picture, the figures are foiled against the background"
is one way to contrast, counterpoint
Derived form noun foil₂
Sample sentences: Somebody ----s something; Something ----s something

2.  foil(v = verb.social) baffle, bilk, cross, frustrate, queer, scotch, spoil, thwart - hinder or prevent (the efforts, plans, or desires) of; "What ultimately frustrated every challenger was Ruth's amazing September surge"; "foil your opponent"
is one way to forbid, foreclose, forestall, preclude, prevent
Derived form noun foiling₁
Sample sentences: Somebody ----s something; Something ----s something

3.  foil(v = verb.contact) - cover or back with foil; "foil mirrors"
is one way to cover
Derived form noun foil₁
Sample sentences: Somebody ----s something; Something ----s something

1.  To tread under foot; to trample. [1913 Webster]
" King Richard . . . caused the ensigns of Leopold to be pulled down and foiled under foot." [1913 Webster]
" Whom he did all to pieces breake and foyle,
In filthy durt, and left so in the loathely soyle." [1913 Webster]

2.  To render (an effort or attempt) vain or nugatory; to baffle; to outwit; to balk; to frustrate; to defeat. [1913 Webster]
" And by foiled." [1913 Webster]
" Her long locks that foil the painter's power." [1913 Webster]

3.  To blunt; to dull; to spoil; as, to foil the scent in chase. Addison. [1913 Webster]

   To defile; to soil. [1913 Webster]

1.  Failure of success when on the point of attainment; defeat; frustration; miscarriage. Milton. [1913 Webster]
" Nor e'er was fate so near a foil." [1913 Webster]

2.  A blunt weapon used in fencing, resembling a smallsword in the main, but usually lighter and having a button at the point. [1913 Webster]
" Blunt as the fencer's foils, which hit, but hurt not." [1913 Webster]
" Isocrates contended with a foil against Demosthenes with a word." [1913 Webster]

3.  The track or trail of an animal. [1913 Webster]

1.  A leaf or very thin sheet of metal; as, brass foil; tin foil; gold foil. [1913 Webster]

2.  A thin leaf of sheet copper silvered and burnished, and afterwards coated with transparent colors mixed with isinglass; -- employed by jewelers to give color or brilliancy to pastes and inferior stones. Ure. [1913 Webster]

3.  Anything that serves by contrast of color or quality to adorn or set off another thing to advantage. [1913 Webster]
"As she a black silk cap on him began
To set, for foil of his milk-white to serve." [1913 Webster]
"Hector has a foil to set him off." [1913 Webster]

4.  A thin coat of tin, with quicksilver, laid on the back of a looking-glass, to cause reflection. [1913 Webster]

5.  The space between the cusps in Gothic architecture; a rounded or leaflike ornament, in windows, niches, etc. A group of foils is called trefoil, quatrefoil, quinquefoil, etc., according to the number of arcs of which it is composed. [1913 Webster]

foil, v. & n.
--v.tr.
1 frustrate, baffle, defeat.
2 Hunting a run over or cross (ground or a scent) to confuse the hounds. b (absol.) (of an animal) spoil the scent in this way.
--n.
1 Hunting the track of a hunted animal.
2 archaic a repulse or defeat.

foil, n.
1 a metal hammered or rolled into a thin sheet (tin foil). b a sheet of this, or of tin amalgam, attached to mirror glass as a reflector. c a leaf of foil placed under a precious stone etc. to brighten or colour it.
2 a person or thing that enhances the qualities of another by contrast.
3 Archit. a leaf-shaped curve formed by the cusping of an arch or circle.

foil, n. a light blunt-edged sword with a button on its point used in fencing.

Derivative:
foilist n.

foil, n. = HYDROFOIL.

Etymology:
abbr.

N  contrariety, contrast, foil, antithesis, oppositeness, contradiction, antagonism, clashing, repugnance, inversion, the opposite, the reverse, the inverse, the converse, the antipodes, the antithesis, the other extreme, contrary, contrarious, contrariant, opposite, counter, dead against, converse, reverse, opposed, antithetical, contrasted, antipodean, antagonistic, opposing, conflicting, inconsistent, contradictory, at cross purposes, negative, hostile, differing toto coelo, diametrically opposite, diametrically opposed, as opposite as black and white, as opposite as light and darkness, as opposite as fire and water, as opposite as the poles, as different as night and day, Hyperion to a satyr, quite the contrary, quite the reverse, no such thing, just the other way, tout au contraire, contrarily, contra, contrariwise, per contra, on the contrary, nay rather, vice versa, on the other hand, all concord's born of contraries, Thesis, antithesis, synthesis.

VB  hinder, impede, filibuster, impedite, embarrass, keep off, stave off, ward off, obviate, avert, antevert, turn aside, draw off, prevent, forefend, nip in the bud, retard, slacken, check, let, counteract, countercheck, preclude, debar, foreclose, estop, inhibit, shackle, restrict, obstruct, stop, stay, bar, bolt, lock, block, block up, choke off, belay, barricade, block the way, bar the way, stop the way, forelay, dam up, put on the brake, scotch the wheel, lock the wheel, put a spoke in the wheel, put a stop to, traverse, contravene, interrupt, intercept, oppose, hedge in, hedge round, cut off, inerclude, interpose, interfere, intermeddle, cramp, hamper, clog, clog the wheels, cumber, encumber, incumber, handicap, choke, saddle with, load with, overload, lay, lumber, trammel, tie one's hands, put to inconvenience, incommode, discommode, discompose, hustle, corner, drive into a corner, run foul of, fall foul of, cross the path of, break in upon, thwart, frustrate, disconcert, balk, foil, faze, feaze, feeze, baffle, snub, override, circumvent, defeat, spike guns, spoil, mar, clip the wings of, cripple, put an extinguisher on, damp, dishearten, discountenance, throw cold water on, spoil sport, lay a wet blanket, throw a wet blanket on, cut the ground from under one, take the wind out of one's sails, undermine, be in the way of, stand in the way of, act as a drag, hang like a millstone round one's neck.

N  arm, arms, weapon, deadly weapon, armament, armaments, armature, panoply, stand of arms, armor, armory, apparatus belli, ammunition, powder, powder and shot, cartridge, ball cartridge, cartouche, fireball, villainous saltpeter, dumdum bullet, explosive, gunpowder, guncotton, mercury fulminate, picrates, pentaerythritol tetranitrate, PETN, high explosive, trinitrotoluene, TNT, dynamite, melinite, cordite, lyddite, plastic explosive, plastique, pyroxyline, sword, saber, broadsword, cutlass, falchion, scimitar, cimeter, brand, whinyard, bilbo, glaive, glave, rapier, skean, Toledo, Ferrara, tuck, claymore, adaga, baselard, Lochaber ax, skean dhu, creese, kris, dagger, dirk, banger, poniard, stiletto, stylet, dudgeon, bayonet, sword-bayonet, sword-stick, side arms, foil, blade, steel, ax, bill, pole-ax, battle-ax, gisarme, halberd, partisan, tomahawk, bowie knife, ataghan, attaghan, yataghan, yatacban, assagai, assegai, good sword, trusty sword, naked sword, cold steel, club, mace, truncheon, staff, bludgeon, cudgel, life preserver, shillelah, sprig, hand staff, quarter staff, bat, cane, stick, knuckle duster, billy, blackjack, sandbag, waddy, gun, piece, firearms, artillery, ordnance, siege train, battering train, park, battery, cannon, gun of position, heavy gun, field piece, mortar, howitzer, carronade, culverin, basilisk, falconet, jingal, swivel, pederero, bouche a feu, petard, torpedo, mitrailleur, mitrailleuse, infernal machine, smooth bore, rifled cannon, Armstrong gun, Lancaster gun, Paixhan gun, Whitworth gun, Parrott gun, Krupp gun, Gatling gun, Maxim gun, machine gun, pompom, ten pounder, small arms, musket, musketry, firelock, fowling piece, rifle, fusil, caliver, carbine, blunderbuss, musketoon, Brown Bess, matchlock, harquebuss, arquebus, haguebut, pistol, postolet, petronel, small bore, breach-loader, muzzle-loader, revolver, repeater, Minis rifle, Enfield rifle, Flobert rifle, Westley Richards rifle, Snider rifle, Martini-Henry rifle, Lee-Metford rifle, Lee-Enfield rifle, Mauser rifle, magazine rifle, needle gun, chassepot, wind gun, air gun, automatic gun, automatic pistol, escopet, escopette, gunflint, gun- lock, hackbut, shooter, shooting iron, six-shooter, shotgun, Uzzi, assault rifle, Kalashnikov, bow, crossbow, balister, catapult, sling, battering ram, gunnery, ballistics, missile, bolt, projectile, shot, ball, grape, grape shot, canister shot, bar shot, cannon shot, langrel shot, langrage shot, round shot, chain shot, balista, ballista, slung shot, trebucbet, trebucket, bullet, slug, stone, brickbat, grenade, shell, bomb, carcass, rocket, congreve, congreve rocket, shrapnel, mitraille, levin bolt, levin brand, thunderbolt, pike, lance, spear, spontoon, javelin, dart, jereed, jerid, arrow, reed, shaft, bolt, boomerang, harpoon, gaff, eelspear, oxgoad, weet-weet, wommerah, cattle prod, chemical mace, en flute, nervos belli pecuniam infinitam.

N  layer, stratum, strata, course, bed, zone, substratum, substrata, floor, flag, stage, story, tier, slab, escarpment, table, tablet, dess, flagstone, board, plank, trencher, platter, plate, lamina, lamella, sheet, foil, wafer, scale, flake, peel, coat, pellicle, membrane, film, leaf, slice, shive, cut, rasher, shaving, integument, eschar, stratification, scaliness, nest of boxes, coats of an onion, monolayer, bilayer, trilayer, lamellar, lamellated, lamelliform, layered, laminated, laminiferous, micaceous, schistose, schistous, scaly, filmy, membranous, pellicular, flaky, squamous, foliated, foliaceous, stratified, stratiform, tabular, discoid, spathic, spathose, trilamellar, graphitic.

aluminium foil, aluminum foil, gold foil, tin foil