WordNet (r) 3.0 (2006):

near miss
    n 1: an accidental collision that is narrowly avoided

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "near miss":
   close call, close shave, close squeak, collision, collision course,
   confrontation, crack-up, crash, encounter, error,
   hairbreadth escape, joining, meeting, miss, mistake, narrow escape,
   narrow squeak, near go, near miss, near thing, rencontre, slip,
   slipup, tight squeeze