[1] : WordNet (r) 2.0

head off
     v : prevent the occurrence of; prevent from happening; "let's
         avoid a confrontation"; "head off a confrontation";
         "avert a strike" syn: debar, obviate, deflect, avert,
          stave off, fend off, avoid, ward off
see also:
debar obviate deflect avert stave off fend off 
avoid ward off 

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

30 moby thesaurus words for "head off":
   avert, bear off, draw aside, ease off, edge off, fly off, gee,
   glance, glance off, go off, haw, jib, make way for, move aside,
   sheer off, shove aside, shunt, shy, shy off, side, sidestep,
   sidetrack, sidle, steer clear of, step aside, switch, turn aside,
   turn away, turn back, veer off

Blow Off >> B Words
Blow Off, definition of term: Blow Off
blow+off_pag1.html

Bite Off >> B Words
Bite Off, definition of term: Bite Off
bite+off_pag1.html

Better Off >> B Words
Better Off, definition of term: Better Off
better+off_pag1.html

Bear Off >> B Words
Bear Off, definition of term: Bear Off
bear+off_pag1.html

Back Off >> B Words
Back Off, definition of term: Back Off
back+off_pag1.html