Definition of: vesicant

(ves′i·kənt) adjective
Blister–producing.
—noun
1. That which produces blisters; a blister.
2. A chemical warfare agent which attacks the skin, as mustard gas or lewisite: also called blister gas. [<NL vesicans, -antis, ppr. of vesicare raise blisters <L vesica a blister, bladder]