mustard agent mus·tar·da·gent uncommon noun 1. a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote Synonymsmustard gasmustard agentblistering agentdichloroethyl sulfidesulfur mustard Related words Broader terms poison gas WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
