WordNet (r) 3.0 (2006):

ward off
    v 1: prevent the occurrence of; prevent from happening; "Let's
         avoid a confrontation"; "head off a confrontation"; "avert
         a strike" [syn: debar, forefend, forfend, obviate,
         deflect, avert, head off, stave off, fend off,
         avoid, ward off]
    2: avert, turn away, or repel; "Ward off danger"

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "ward off":
   about the bush, anticipate, avert, bar, beat around, beat back,
   beat off, beg the question, block, brush off, chase, chase away,
   chase off, check, counter, cut, debar, deflect, deter, discourage,
   dishearten, dismiss, dodge, drive away, drive back, duck,
   equivocate, estop, exclude, fence, fend, fend off, forbid,
   foreclose, forestall, hedge, help, hem and haw, hinder,
   hold at bay, hold off, keep at bay, keep from, keep off, obstruct,
   obviate, pack off, parry, preclude, prevent, prohibit, pull away,
   pull back, push back, pussyfoot, put back, put off, rebuff, rebut,
   recoil, refuse, repel, repulse, rule out, save, send away,
   send off, send packing, sheer off, shift, shift off, shrink, shy,
   shy away, shy off, sidestep, snub, spurn, stave off, step aside,
   stop, swerve, thrust back, turn aside, turn back