foul up

verb

fouled up; fouling up; fouls up

transitive verb

1

: to make dirty : contaminate

2

: to spoil by making mistakes or using poor judgment : confuse

3

: entangle, block

fouled up communications

intransitive verb

: to cause a foul-up : bungle

… it was his fault. He had fouled up.

—Pat Frank

Synonyms of foul up

• fumble
• blow
• screw up
• murder
• ruin

Examples of foul up in a Sentence

tried not to foul up the football play

unfortunately, I fouled up and in my e-mail gave everyone the wrong date for the meeting

Recent Examples on the Web

In the end, though, neither an explosion nor a giant spill of fluid that could foul up waterways and the ocean occurred. —Hannah Fry, Los Angeles Times, 27 May 2026

An incorrect connection or approach can foul up a line, damage a plane or cause an accident. —Tara Copp The Washington Post, Arkansas Online, 25 May 2026

On the ensuing power play, the Wild were doing a fine job when two of their normally reliable penalty killers fouled up. —Michael Russo, New York Times, 21 Apr. 2026

There was Anthony Edwards brashly asking Watson if the Nuggets planned to foul up three at the end of regulation, before draining an incredible shot to force overtime. —Bennett Durando, Denver Post, 12 Apr. 2026

Word History

First Known Use

1880, in the meaning defined at transitive sense 1

Rhymes for foul up

• backup
• blowup
• breakup
• buildup
• checkup
• cleanup
• holdup
• hookup
• lineup
• lockup
• makeup
• markup

Kids Definition

foul-up

1 of 2 noun

ˈfau̇-ˌləp

: an instance of fouling up : a state of being fouled up

foul up

2 of 2 verb

(ˈ)fau̇-ˈləp

: to spoil by bad work or stupidity : botch

fouled up the surprise attack