From Longman Dictionary of Contemporary Englishfoul up phrasal verb informal1 to do something wrong or spoil something by making mistakes → foul-up We can’t afford to foul up this time.foul something ↔ up Glen completely fouled up the seating arrangements.2 foul something ↔ up to make something very dirty, especially with waste He lit a cigarette and started to foul up the air with stinging yellow smoke. → foul→ See Verb tablefoul-upˈfoul-up noun [countable] informal MISTAKEa problem caused by a stupid or careless mistake → foul up a computer system foul-up
Examples from the Corpus
foul-up• I had to retake my driver's test because of some clerical foul-up. 