WordNet (r) 3.0 (2006):

answer for
    v 1: furnish a justifying analysis or explanation; "I can't
         account for the missing money" [syn: account, answer
         for]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "answer for":
   accept obligation, accept the responsibility, act for, agree to,
   appear for, back up, be accepted for, be answerable for,
   be regarded as, be responsible for, be security for,
   be sponsor for, be taken as, bind, commission, commit, contract,
   count for, deputize, engage, front for, go as, go bail for, go for,
   have an understanding, obligate, pass as, pass for, pinch-hit for,
   represent, serve as, shake hands on, speak for, sponsor,
   stand in for, stand sponsor for, substitute for, take the blame,
   take the vows, understudy, undertake