A piece of thin and flexible sheet metal.

Roget 14: contrariety, contrast, foil, antithesis, oppositeness; contradiction; antagonism etc. (opposition) 708; clashing, repugnance.    inversion etc. 218; the opposite, the reverse, the inverse, the converse, the antipodes, the antithesis, the other extreme.    ... show more

Roget 204: 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 etc. (covering) 223; eschar^†.    stratification, scaliness, nest of boxes, coats of an onion.    monolayer; bilayer; trilayer [Bioch.].    ... show more

Roget 727: arm, arms; weapon, deadly weapon; armament, armaments, armature; panoply, stand of arms; armor etc. (defense) 717; armory etc. (store) 636; apparatus belli [Lat.].    ammunition; powder, powder and shot; cartridge; ball cartridge, cartouche, fireball; villainous saltpeter" [Henry IV]; dumdum bullet.    explosive; gunpowder, guncotton; mercury fulminate; picrates; pentaerythritol tetranitrate, PETN.    high explosive; trinitrotoluene, TNT; dynamite, melinite^†, cordite, lyddite, plastic explosive, plastique; pyroxyline^†.    [knives and swords: list] 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 [Fr.]; firearms; artillery, ordnance; siege train, battering train; park, battery; cannon, gun of position, heavy gun, field piece [Fr.], mortar, howitzer, carronade^†, culverin^†, basilisk; falconet, jingal^†, swivel, pederero^†, bouche a feu [Fr.]; petard, torpedo; mitrailleur [Fr.], mitrailleuse [Fr.]; 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 [Fr.], 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 [U.S.], six-shooter [U.S.], shotgun; Uzzi, assault rifle, Kalashnikov.    bow, crossbow, balister^†, catapult, sling; battering ram etc. (impulse) 276; gunnery; ballistics etc. (propulsion) 284.    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 [Fr.]; 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.    ... show more

Dutch: folie, floret, Aluminiumfolie
Polish: folia

Anything that serves by contrast to call attention to another thing's good qualities:
— Pretty girls like plain friends as foils.

synonym: enhancer.

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.

synonym: hydrofoil.

Picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector.

synonym: transparency.

Dutch: transparant
Polish: przezrocze, diapozytyw, przeźrocze

A light slender flexible sword tipped by a button.

Polish: floret

Enhance by contrast.

Hinder or prevent (the efforts, plans, or desires) of:
— Foil your opponent.

synonyms: baffle, bilk, cross, frustrate, queer, scotch, spoil, thwart.

Roget 706: hinder, impede, filibuster [U.S.], 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 [Law]; inhibit etc. 761; shackle etc. (restrain) 751; 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 etc. (close) 261; put on the brake etc. n.; scotch the wheel, lock the wheel, put a spoke in the wheel; put a stop to etc. 142; traverse, contravene; interrupt, intercept; oppose etc. 708; hedge in, hedge round; cut off; inerclude^†.    interpose, interfere, intermeddle etc. 682.    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 [U.S.]; baffle, snub, override, circumvent; defeat etc. 731; spike guns etc. (render useless) 645; spoil, mar, clip the wings of; cripple etc. (injure) 659; put an extinguisher on; damp; dishearten etc. (dissuade) 616; 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.    ... show more

Dutch: afweren, dwarsbomen, frustreren, torpederen

Cover or back with foil.

Dutch: frustreren