foil

1 of 2

verb (1)

ˈfȯi(-ə)l 

foiled; foiling; foils

transitive verb

1

a

: to prevent from attaining an end : defeat

They are always able to foil their enemies.

Her accident foiled her from becoming a dancer.

b

: to bring to naught : thwart

foiled the plot

Police foiled an attempted robbery.

2

obsolete : trample

foil

2 of 2

verb (2)

foiled; foiling; foils

transitive verb

1

: to back or cover with foil

2

: to enhance by contrast

Synonyms of foil

Verb (1)

• frustrate
• thwart
• baffle
• hamper
• prevent
• defeat

Choose the Right Synonym for foil

frustrate, thwart, foil, baffle, balk mean to check or defeat another's plan or block achievement of a goal.

frustrate implies making vain or ineffectual all efforts however vigorous or persistent.

frustrated attempts at government reform

thwart suggests frustration or checking by crossing or opposing.

the army thwarted his attempt at a coup

foil implies checking or defeating so as to discourage further effort.

foiled by her parents, he stopped trying to see her

baffle implies frustration by confusing or puzzling.

baffled by the maze of rules and regulations

balk suggests the interposing of obstacles or hindrances.

officials felt that legal restrictions had balked their efforts to control crime

Examples of foil in a Sentence

Verb (1)

in popular fiction the hero will always foil the villain's plans

Recent Examples on the Web

Verb

The full-head foiling technique is a big step away from balayage and the more relaxed, live-in color trends that dominated the space since the pandemic. —Reece Andavolgyi, InStyle, 5 June 2026

The rally would play out, Shnaider would make the first move and either make an error or be foiled by Chwalińska’s equally remarkable ability to turn defense into attack. —Charlie Eccleshare, New York Times, 4 June 2026

Navier’s flagship, the N30, is a 30-foot electric foiling yacht that can carry up to eight passengers and a driver. —Rachel Cormack, Robb Report, 2 June 2026

SpaceX nearly launched its Starship rocket on Thursday amid much pomp and circumstance in South Texas, only to be foiled by a ground system issue. —Eric Berger, ArsTechnica, 22 May 2026

Word History

Etymology

Verb (1)

Middle English foilen "to trample, tread upon, mortify (the flesh), oppress," alteration of fullen "to full (cloth), trample down, oppress," perhaps by analogy with loanwords from French with palatal l that result in variants with -oi- and -u-, as coilen, cullen "to select for quality, pick out, cull entry 1" — more at full entry 5

First Known Use

Verb (1)

14th century, in the meaning defined at sense 2

Verb (2)

1611, in the meaning defined at sense 1

Phrases Containing foil

• aluminum foil
• silver foil

Rhymes for foil

• boil
• broil
• coil
• oil
• roil
• soil
• spoil
• toil
• voile
• aerofoil
• cinquefoil
• hydrofoil

Kids Definition

foil

1 of 3 verb

ˈfȯi(ə)l 

: to prevent from achieving a goal : defeat

foil a plot

foil

2 of 3 noun

1

: a very thin sheet of metal

tin or aluminum foil

2

: one that serves as a contrast to another

acted as a foil for the comedian

foil

3 of 3 noun

: a fencing weapon having a light flexible blade with a blunt point

Etymology

Verb

Middle English foilen "to trample underfoot," from early French fuller, fouler "to shrink and thicken (cloth), trample underfoot," from Latin fullare "to shrink and thicken (cloth)"

Noun

Middle English foil "leaf," from early French fuille, foille (same meaning), derived from Latin folium "leaf" — related to foliage

Noun

origin unknown

Medical Definition

foil

noun

ˈfȯil 

: very thin sheet metal (as of gold or platinum) used especially in filling teeth