foul up

Blunder or cause to blunder; botch, ruin. For example, He's fouled up this report, but I think we can fix it, or Our plans were fouled up by the bad weather. This expression is widely believed to have originated as a euphemism for fuck up. [Colloquial; c. 1940]

Definition: make a mess of
Antonyms: fix, mend, organize

The verb has one meaning:

Meaning #1: make a mess of, destroy or ruin
  Synonyms: botch, bumble, fumble, botch up, muff, blow, flub, screw up, ball up, spoil, muck up, bungle, fluff, bollix, bollix up, bollocks, bollocks up, bobble, mishandle, louse up, mess up, fuck up