Source : Webster's Revised Unabridged Dictionary (1913)

Vesicant \Ves"i*cant\, n. [L. vesica blister: cf. F.
   v['e]sicant.] (Med.)
   A vesicatory.

Source : WordNet®

vesicant
     adj : causing blisters [syn: {vesicatory}]
     n : a chemical agent that causes blistering [syn: {vesicatory}]