foil Definition

foil¹
verb

foiled, foiling
1. To prevent, thwart or frustrate someone or something.

Thesaurus: thwart, obstruct, outsmart, outwit, frustrate, baffle, elude, counter, stop, stump, check, circumvent; Antonym: abet.

Etymology: 16c: from French fuler to trample.

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foil²
noun

1a. Metal beaten or rolled out into thin sheets;


Example: tinfoil
Example: gold foil
2. A thin metallic coating (usually mercury or a mercury-alloy) on a piece of glass which produces a reflection, forming the backing of a mirror.
3. A thin leaf of metal put under a precious stone to show it to advantage.
4. Someone or something that acts as a contrast to, and brings out, the superior or different qualities of another.

Thesaurus: contrast, complement, counterpart, antithesis.
5. archit.
In tracery, particularly of Gothic architecture: a small leaf-shaped curve or arc, forming a cusp where two foils meet.
6. A hydrofoil or an aerofoil.

Derivative: foilborne
adj

Said of a craft: lifted up from the water or travelling along the water on hydrofoils.

Etymology: 14c: from French foil leaf, from Latin folium.

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foil³
noun

1. fencing.
A long slender sword with a blunt edge and a point protected by a button.

Etymology: 16c.