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

: indecent and offensive

foul language

He has a foul mouth. [= he speaks in an indecent and offensive way]

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

see also:

cry foul

foul

3 of 4

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

foul

4 of 4

adverb

: in a foul manner : so as to be foul

Synonyms of foul

Adjective

• disgusting
• ugly
• sickening
• horrible
• awful
• offensive
• hideous
• obscene
• obnoxious
• shocking
• nasty
• dreadful

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

If a ball is hit into foul territory and a fan makes the grab, the batter is out. — Idaho Statesman, 27 July 2026

Hernández went 0-for-2 with a sacrifice fly, demonstrated zone awareness while drawing two walks, and made the play of the night, ranging far into foul ground after gloving a ground ball that threaded the chalk line. — Andrew Baggarly, New York Times, 26 July 2026

Noun

Things looked even better for Argentina when Spain had a goal disallowed for what appeared to be a very soft foul by Mikel Merino on an Albiceleste defender that ruled out Williams’ effort. — Patrick Sung Cuadrado, CNN Money, 20 July 2026

Alexis Mac Allister’s early foul on Dani Olmo was badly timed and nasty. — Adam Crafton, New York Times, 20 July 2026

Verb

On Monday, after homering in the second inning and striking out in the third, Kuroda-Grauer was back at the dish and fouled a pitch straight into his own crotch. — Matt Reigle Outkick, FOXNews.com, 22 July 2026

Then Nicolas Tagliafico, a poor defender up against a great attacker in Lamine Yamal, took to attempting to foul the winger in four different ways at once, but most unpleasantly grazed his studs down Yamal’s calf. — Adam Crafton, New York Times, 20 July 2026

Adverb

Perhaps unsurprisingly, many of these users called foul on the update itself, which in turn led to unofficial support forums and social media accounts advising users not to install it. — Davey Winder, Forbes.com, 20 July 2026

No foul was called on the play, and Stewart was not assessed a flagrant or reviewed for it. — Jackson Thompson Outkick, FOXNews.com, 19 July 2026

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

before the 12th century, in the meaning defined above

Phrases Containing foul

• cry foul
• fall foul of
• foul ball
• foul line
• 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