WordNet (r) 3.0 (2006):

screw up
    v 1: make more intense; "Emotions were screwed up" [syn: heat
         up, hot up, screw up]
    2: make a mess of, destroy or ruin; "I botched the dinner and we
       had to eat out"; "the pianist screwed up the difficult
       passage in the second movement" [syn: botch, bodge,
       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, foul up, mess up, fuck up]
    3: screw or turn higher
    4: twist into a strained configuration; "screw up one's face"