foul

1 of 4

adjective

ˈfau̇(-ə)l 

1

a

: offensive to the senses : loathsome

the foul odor of rotten eggs

b

: filled or covered with offensive matter

foul bins of filth

2

: being odorous and impure : polluted

foul air

3

a

: morally or spiritually odious : detestable

a foul crime

b

: notably unpleasant or distressing : wretched, horrid

in a foul mood

4

: obscene, abusive

foul language

5

a

: being wet and stormy

foul weather

b

: obstructive to navigation

a foul tide

6

a

: treacherous, dishonorable

fair means or foul

b

: constituting an infringement (see infringe sense 1) of rules in a game or sport

a foul blow in boxing

7

: being outside the foul lines in baseball

… a foul fly that was snagged by a fan in the stands.

—E. M. Swift

8

: containing marked-up corrections

a foul manuscript

foul proofs

9

: full of dirt or mud

10

: encrusted, clogged, or choked with a foreign substance

the chimney was foul and smoked badly

11

: placed in a situation that impedes physical movement : entangled

a foul fishing line

12

dialectal British : homely, ugly

foully

ˈfau̇(l)-lē 

adverb

foulness noun

foul

2 of 4

noun

1

a

: an infringement of the rules in a game or sport

b

: free throw

2

: foul ball

3

: an entanglement or collision especially in angling or sailing

4

archaic : something foul

foul

3 of 4

verb

fouled; fouling; fouls

transitive verb

1

: to make foul: such as

a

: to make dirty : pollute

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

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

foul

4 of 4

adverb

: in a foul manner : so as to be foul

Synonyms

Adjective

• turbulent
• bleak
• dirty
• rough
• rainy

Verb

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

Choose the Right Synonym for foul

dirty, filthy, foul, nasty, squalid mean conspicuously unclean or impure.

dirty emphasizes the presence of dirt more than an emotional reaction to it.

a dirty littered street

filthy carries a strong suggestion of offensiveness and typically of gradually accumulated dirt that begrimes and besmears.

a stained greasy floor, utterly filthy

foul implies extreme offensiveness and an accumulation of what is rotten or stinking.

a foul-smelling open sewer

nasty applies to what is actually foul or is repugnant to one expecting freshness, cleanliness, or sweetness.

it's a nasty job to clean up after a sick cat

In practice, nasty is often weakened to the point of being no more than a synonym of unpleasant or disagreeable.

had a nasty fall

his answer gave her a nasty shock

squalid adds to the idea of dirtiness and filth that of slovenly neglect.

squalid slums

All these terms are also applicable to moral uncleanness or baseness or obscenity.

dirty then stresses meanness or despicableness

don't ask me to do your dirty work

, while filthy and foul describe disgusting obscenity or loathsome behavior

filthy street language

a foul story of lust and greed

, and nasty implies a peculiarly offensive unpleasantness.

a stand-up comedian known for nasty humor

Distinctively, squalid implies sordidness as well as baseness and dirtiness.

engaged in a series of squalid affairs

Examples of foul in a Sentence

Adjective

the foul odor of rotten eggs

The medicine left a foul taste in my mouth.

The weather has been foul all week.

Noun

He hit several fouls in a row.

Verb

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

Adjective

Cats often express their dismay at being excluded from your travel plans by peeing in your luggage, but of course, cat urine is not the only thing that can cause a foul odor in your suitcase. —Jolie Kerr, Better Homes & Gardens, 26 June 2025

Police responded to a 911 call about a foul odor, and found Burgos’ apartment door unlocked in the building that offers affordable units for senior citizens. —Nicholas Williams, New York Daily News, 19 June 2025

Noun

There were multiple threads on Reddit calling foul on the story. —Lizz Schumer, People.com, 7 July 2025

First, Kelvin Yeboah’s long dribble down the left flank was dangerous and forced an FC Dallas foul just outside the 18-yard box. —Andy Greder, Twin Cities, 5 July 2025

Verb

Villa failed to secure Champions League football after losing 2-0 against United on the final day of the season, with Martinez receiving a red card after fouling Rasmus Hojlund outside the penalty area. —Mark Critchley, New York Times, 12 July 2025

Batted balls that are caught in the air are outs; strikeouts occur when a batter swings through one pitch or fouls off two of them. —Don Norcross, San Diego Union-Tribune, 11 July 2025

Adverb

Eight people died when the weather suddenly turned foul, turning the lake into a mini-ocean. —Rick Hurd, Mercury News, 3 July 2025

His first pitch as a Dodger was a 98 MPH fastball that Fernando Tatís bounced foul. —Dan Freedman, Forbes.com, 17 June 2025

Word History

Etymology

Adjective and Noun

Middle English, from Old English fūl; akin to Old High German fūl rotten, Latin pus pus, putēre to stink, Greek pyon pus

First Known Use

Adjective

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

Noun

before the 12th century, in the meaning defined at sense 4

Verb

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

Adverb

13th century, in the meaning defined above

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