crystal violet crys·tal·vio·let uncommon noun 1. a green crystal (violet in water) used as a dye or stain or bactericide or fungicide or anthelmintic or burn treatment Synonymsgentian violetcrystal violet Related words Broader terms stainantibacterialantifungalvermifuge WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.