noun

FOIL

foyl

noun

A very thin, flexible sheet of metal, especially aluminum, used for wrapping food.

"She wrapped the leftovers in foil before putting them in the fridge."

A person or thing that highlights another's qualities by contrast, especially in a story.

"The clumsy sidekick acts as a foil to the graceful hero."

A thin fencing sword with a blunted tip, used in the sport of fencing.

"The fencers saluted each other with their foils before the match."

verb

To prevent a plan, attempt, or plot from succeeding.

"Police foiled the robbery before it could take place."

"Her quick thinking foiled his attempt to cheat."

How to Use FOIL

Learner’s notes

In plain EnglishThin metal sheeting, or to stop a plan from working, or a contrasting character in a story.

Common mistake

Don't confuse this "foil" (a character contrast) with the unrelated FOIL acronym used for multiplying binomials in algebra — same spelling, totally different meaning.

Common pairings

aluminum foil foil a plot act as a foil

Word Forms

FOILed past tense, foiled past tense, foiled past tense, foiled past tense, foils plural, foils plural, foils plural, FOILs singular, foils singular, foils singular, foils singular

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Fill the Gap

Can you complete this real example?

She wrapped the leftovers in _____ before putting them in the fridge.

Etymology

The "prevent" and "thin metal sheet" senses come from separate Old French roots meaning "to trample" and "leaf" respectively — both eventually collapsed into the single English spelling "foil."

Rhymes for FOIL

oil soil boil toil coil spoil recoil turmoil tinfoil topsoil

See all rhymes for FOIL →