foul

verb

fouled; fouling; fouls

transitive verb

1

: to make foul: such as

a

: to make dirty : pollute

fouled the water

b

: to tangle or come into collision with

c

: to encrust with a foreign substance

a ship's bottom fouled with barnacles

d

: obstruct, block

2

: dishonor, discredit

3

: to commit a foul against

was fouled while attempting a shot on goal

4

: to hit (a baseball) foul

intransitive verb

1

: to commit a violation of the rules in a sport or game

2

: to hit a foul ball

3

: to become or be foul: such as

a

: decompose, rot

b

: to become encrusted, clogged, or choked with a foreign substance

c

: to become entangled or come into collision

Synonyms of foul

• dirty
• stain
• blacken
• muck
• soil
• mess
• muddy

Examples of foul in a Sentence

pollutants that foul the air

She fouled on her first long jump attempt.

He was fouled as he attempted the shot.

He kept fouling pitches into the stands.

Recent Examples on the Web

His minutes were limited against Cleveland, and Brown often used him as, for lack of a better word, bait to trick the Cavs into fouling him quickly and putting the Knicks into the bonus. —Joe Vardon, New York Times, 2 June 2026

Alexa Spaanstra fouled Jayden Perry in the box for the penalty kick that Wilson converted for her fifth goal of the season. —ABC News, 30 May 2026

Tolle threw 27 pitches in the third, 28 in the fourth and 21 in the fifth, and over those three innings there were four at-bats where a Braves hitter fouled off three or more pitches. —Mac Cerullo, Boston Herald, 28 May 2026

Lee had fouled off a pair of pitches to begin the at-bat, falling behind 0-2 before his big swing. —Betsy Helfand, Twin Cities, 27 May 2026

Word History

First Known Use

before the 12th century, in the meaning defined at intransitive sense 1

Phrases Containing foul

• cry foul
• fall foul of
• foul ball
• foul line
• foul mouth
• foul of
• foul out
• foul play
• foul shot
• foul tip
• foul trouble
• foul-up
• personal foul
• professional foul
• team foul
• technical foul

Rhymes for foul

• foule
• fowl
• growl
• howl
• jowl
• owl
• prowl
• scowl
• afoul
• wildfowl
• waterfowl

Kids Definition

foul

1 of 4 adjective

ˈfau̇(ə)l 

1

a

: disgusting in looks, taste, or smell

foul odor

b

: full of or covered with dirt

foul clothes

2

a

: detestable

a foul crime

b

: notably unpleasant or bad

a foul mood

c

: being vulgar or insulting

foul language

3

: being wet and stormy

foul weather

4

a

: very unfair

fair means or foul

b

: breaking a rule in a game or sport

a foul blow in boxing

5

: being outside the foul lines in baseball

a foul grounder

foully

ˈfau̇(l)-lē 

adverb

foulness

ˈfau̇(ə)l-nəs

noun

foul

2 of 4 noun

1

: an entanglement or collision in fishing or sailing

2

a

: a breaking of the rules in a game or sport

b

: free throw

3

: foul ball

foul

3 of 4 verb

1

: to make or become foul or filthy

foul the air

foul a stream

2

a

: to make a foul in a game or sport

b

: to hit a foul ball

3

: to become or cause to become entangled

foul the lines

foul

4 of 4 adverb

: in a foul manner : so as to be foul