foul

1 adjective

1 SMELL/TASTE a foul smell or taste is very unpleasant: I gulped down some water to take the foul taste out of my mouth. | foul-tasting/foul-smelling: The bags of garbage had been piled up in a foul-smelling heap.

2 in a foul mood/temper especially BrE in a very bad mood and likely to get angry: He's in a foul mood today, isn't he?

3 UNPLEASANT especially BrE very unpleasant: I've had an absolutely foul day.

4 AIR/WATER very dirty: The water in the harbour was foul with oil.

5 foul language rude and offensive words: I've never heard such foul language in all my life!

6 WEATHER especially BrE if the weather is foul, it is stormy and windy, with a lot of rain or snow

7 EVIL especially literary evil or cruel: foul deeds

—see also: by fair means or foul fair 1 (13), fall foul of fall 1 (28) — foully adverb — foulness noun (U) 2 verb

1 (I, T)

a) if a player fouls in a game of sport, or fouls another player, they do something that is not allowed by the rules: An Everton player had been fouled in the penalty area.

b) to hit a ball outside the limit of the playing area in baseball: On average, most batters foul at least one ball in each at bat.

2 formal to make something very dirty, especially with waste: A thick column of black smoke rose from the wreck, fouling the air.

3 also foul up (I, T) if a rope, chain, or part of a machine fouls or if something fouls it, it twists or cannot move properly: Check that nothing can foul the moving parts.

foul up phrasal verb informal

1 (transitive foul something up) to spoil something: The weather really fouled up our vacation plans.

2 (intransitive, transitive foul something up) to do something wrong or spoil something by making mistakes: Glen completely fouled up the seating arrangements.

3 noun (C) an action in a sport that is against the rules: That was a foul - he touched the ball with his hand!