foil

plural foils

1. countableuncountableA very thin sheet of metal.
2. countableuncountablechiefly Euro EnglishA very thin sheet of plastic.
3. uncountableThin aluminium/aluminum (or, formerly, tin) used for wrapping food.

   wrap the sandwich up in foil

   1 more example

   Police found a trapdoor, leading to a basement where boxes labelled as containing dried goods held packages of phones wrapped up in foil, as well as £44,665 in cash.

   2026 September 25, Sonja Jessup, “How 'largest phone smuggling network' was uncovered”, in BBC News, archived from the original on 25 Sep 2026, retrieved 25 Sep 2026

   Synonyms: aluminium foil, silver foil, silver paper, tin foil

4. countableuncountableA thin layer of metal put between a jewel and its setting to make it seem more brilliant.
5. countablefigurativelyuncountableauthorshipIn literature, theatre/theater, etc., a character who helps emphasize the traits of the main character and who usually acts as an opponent or antagonist, but can also serve as the sidekick of the protagonist.

   As Puss comes to realize his legendary status is not a substitute for interpersonal connection, his interactions with Kitty and the therapy dog start to take on a surprising amount of weight, while Goldilocks serves as a well-realized foil who has more in common with Puss that is at first apparent.

   2022 December 20, Leigh Monson, “Puss In Boots: The Last Wish review: Antonio Banderas leads the best film yet in the Shrek franchise”, in AV Club, archived from the original on 14 Mar 2023

   1 more example

   Whereas the female invests heavily in the wake of conception, the male invests heavily prior to conception. Hitherto, the male has been regarded as the mere foil to the heavy investment in reproduction that renders the female the logjam (the limiting factor) in reproduction – reproduction overall is expandable by increasing the number of females, not by increasing the number of males.

   2019, Steve Paul Moxon, “The Sexes Serve to Purge Mutations by Selection on Males, Boosting the Function of Sex to Maintain Genomic Integrity]”, in New Male Studies, volume 8, number 1, pages 46–47 of 25–51, archived from the original on 06 Aug 2021

6. countablefigurativelyuncountableAnything that acts by contrast to emphasise the characteristics of something.

   1725-1726, William Broome, The Odyssey Hector has also a foil to set regard

   1 more example

   As she a black silk cap on him begun / To set, for foil of his milk-white to serve.

   The New Arcadia

   a. 1587, Philippe Sidnei [i.e., Philip Sidney], “(please specify the folio)”, in [Fulke Greville; Matthew Gwinne; John Florio], editors, The Countesse of Pembrokes Arcadia [The New Arcadia], London: […] [John Windet] for William Ponsonbie, published 1590, →OCLC

7. countableuncountablefencingA very thin sword with a blunted (or foiled) tip.

   1784-1810, William Mitford, History of Greece Socrates contended with a foil against Demosthenes with a sword.

   2 more examples

   Blunt as the fencer's foils, which hit, but hurt not.

   1598–1599 (first performance), William Shakespeare, “Much Adoe about Nothing”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene ii]

   The country’s fencing federation has officially recognised lightsaber duelling as a competitive sport, granting the weapon from George Lucas’s space saga the same status as the foil, epee and sabre, the traditional blades used at the Olympics.

   2019 February 19, “Lightsaber duelling registered as official sport in France”, in The Guardian, archived from the original on 08 Nov 2020

8. countableuncountableA thin, transparent plastic material on which marks are made and projected for the purposes of presentation. See transparency.
9. countableuncountableA premium trading card with a glossy finish.

   I personally would collect all the foils from Base Set before this one, but the market is what the market is.

   2016, Pojo's Unofficial Big Book of Pokémon, Triumph Books

10. countableuncountablegovernmentA stylized flower or leaf.
11. abbreviationclippingcountableuncountablegeographyClipping of hydrofoil.
12. abbreviationclippingcountableuncountableaerodynamicsClipping of aerofoil/airfoil.

present singular third person foils · participle present foiling · participle past foiled · past foiled

1. transitiveTo cover or wrap with foil.
2. abbreviationclippingnauticalClipping of hydrofoil.

present singular third person foils · participle present foiling · participle past foiled · past foiled

1. To prevent (something) from being accomplished.

   They foiled my plans.

   Synonyms: put the kibosh on, scupper, thwart

2. To prevent (someone) from accomplishing something.

   I was foiled by my superior.

   5 more examples

   And at the field fought before Bebriacum, ere the battailes joyned, tvvo Ægles had a conflict and bickered together in all their fights: and vvhen the one of them was foyled and overcome, a third came at the very inſtant from the ſunne riſing and chaſed the Victreſſe avvay.

   1606, Caius [i.e., Gaius] Suetonius Tranquillus, “The Historie of Flavius Vespatianus Augustus”, in Philêmon Holland, transl., The Historie of Twelve Cæsars Emperours of Rome. […], London: […] [Humphrey Lownes and George Snowdon] for Matthew Lownes, →OCLC, section 5, page 243

   And by mortal man at length am foil'd.

   1697, Virgil, “The Seventh Book of the Æneis”, in John Dryden, transl., The Works of Virgil: Containing His Pastorals, Georgics, and Æneis. […], London: […] Jacob Tonson, […], →OCLC

   her long locks that foil the painter's power

   1812, Lord Byron, “Canto I”, in Childe Harold’s Pilgrimage. A Romaunt, London: […] [F]or John Murray, […]; William Blackwood, Edinburgh; and John Cumming, Dublin; by Thomas Davison, […], →OCLC, stanza LV

   Perhaps you think you love me now but it is only for an instant, and because you are foiled.

   1848 November – 1850 December, William Makepeace Thackeray, chapter 28, in The History of Pendennis. […], volume (please specify |volume=I or II), London: Bradbury and Evans, […], published 1849–1850, →OCLC

   First, former Toffee Mikel Arteta sent Walcott racing clear but instead of shooting he squared towards Ramsey, who was foiled by Tony Hibbert.

   2011 December 10, David Ornstein, “Arsenal 1 - 0 Everton”, in BBC Sport

3. To blunt; to dull; to spoil.

   they foil the scent of one another.

   1711 August 10 (Gregorian calendar), [Joseph Addison], “MONDAY, July 31, 1711”, in The Spectator, number (please specify the issue number); republished in Alexander Chalmers, editor, The Spectator; a New Edition, […], volume (please either specify the issue number or |volume=I to VI), New York, N.Y.: D[aniel] Appleton & Company, 1853, →OCLC

   Synonyms: mar, mess up, vitiate, ball up, blight, bumble, botch, bugger up

4. obsoleteTo tread underfoot; to trample.

   King Richard […] caused the ensigns of Leopold to be pulled down and foiled underfoot.

   1603, Richard Knolles, The Generall Historie of the Turkes

   1 more example

   Whom he did all to pieces breake and foyle, / In filthy durt, and left so in the loathely soyle.

   1596, Edmund Spenser, “Book V, Canto XXXIII”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, →OCLC

plural foils

1. Failure when on the point of attainment; defeat; frustration; miscarriage.

   Nor e'er was fate so near a foil.

   1685, John Dryden, Threnodia Augustalis

   1 more example

   Fame is no plant that grows on mortal foil

   1671, John Milton, “(please specify the page)”, in Paradise Regain’d. A Poem. In IV Books. To which is Added, Samson Agonistes, London: […] J[ohn] M[acock] for John Starkey […], →OCLC

2. One of the incorrect answers presented in a multiple-choice test.

plural foils

1. hobbiesThe track of an animal.

   […]but after giving her a dodge, here's another b— follows me upon the foil.

   1749, Henry Fielding, chapter IV, in The History of Tom Jones, a Foundling, volume (please specify |volume=I to VI), London: A[ndrew] Millar, […], →OCLC, book VII

   Synonyms: spoor

present singular third person foils · participle present foiling · participle past foiled · past foiled

1. mathematicsTo expand a product of two or more algebraic expressions, typically binomials.

present singular third person foils · participle present foiling · participle past foiled · past foiled

1. obsoleteTo defile; to soil.

   Synonyms: befile, stain, sully, assoil, beclart, bedaub, bedirty, imbrue (especially with blood)

plural foils

1. architectureA small arc in the tracery of a window, etc.

1. mnemonicAn acronym for the algorithm for multiplying two binomials.

present singular third person FOILs · participle present FOILing · participle past FOILed · past FOILed

1. transitiveTo apply the FOIL algorithm to.