mustard agent vs mustard gas

mustard agent and mustard gas both are nouns.

Word	Noun	Adjective	Verb	Adverb
mustard agent	Yes	No	No	No
mustard gas	Yes	No	No	No

As nouns, mustard agent and mustard gas are synonyms defined as:

mustard agent and mustard gas: a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote

Other synonyms of mustard agent include blistering agent, dichloroethyl sulfide, sulfur mustard.

mustard agent (noun)	mustard gas (noun)
a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote	a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote