[1] : WordNet (r) 2.0

push back
     n : the act of forcing the enemy to withdraw syn: rollback
     v : cause to move back by force or influence; "repel the enemy";
         "push back the urge to smoke"; "beat back the invaders"
         syn: repel, drive, repulse, force back, beat
         back ant: attract
see also:
rollback repel drive repulse force back beat back 
attract 

[2] : Moby Thesaurus II by Grady Ward, 1.0

39 moby thesaurus words for "push back":
   beat back, beat off, block, brush off, chase, chase away,
   chase off, check, counter, cut, dismiss, drive away, drive back,
   fend, fend off, hinder, hold at bay, hold off, keep at bay,
   keep off, obstruct, pack off, parry, put back, rebuff, refuse,
   repel, repulse, send away, send off, send packing, snub, spurn,
   stave off, stop, thrust back, turn aside, turn back, ward off

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