WordNet (r) 3.0 (2006):

debunk
    v 1: expose while ridiculing; especially of pretentious or false
         claims and ideas; "The physicist debunked the psychic's
         claims" [syn: debunk, expose]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "debunk":
   awaken, break the spell, burst the bubble, correct, disabuse,
   disappoint, discover, disenchant, disillude, disillusion,
   disillusionize, enlighten, expose, let down easy, let in on,
   prick the bubble, put straight, set right, set straight, show up,
   tell the truth, unblindfold, uncharm, uncloak, undeceive, undress,
   unmask, unshroud, unspell, wake up