The Collaborative International Dictionary of English v.0.48:

foul-up \foul-up\ n.
   an embarrassing mistake.

   Syn: blunder, blooper, bungle, flub, botch, boner, boo-boo,
        misdoing.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

foul-up
    n 1: an embarrassing mistake [syn: blunder, blooper,
         bloomer, bungle, pratfall, foul-up, fuckup,
         flub, botch, boner, boo-boo]