nerve gas vs nerve agent

nerve gas and nerve agent both are nouns.

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

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

nerve gas and nerve agent: a toxic gas that is inhaled or absorbed through the skin and has harmful effects on the nervous and respiratory system

nerve gas (noun)	nerve agent (noun)
a toxic gas that is inhaled or absorbed through the skin and has harmful effects on the nervous and respiratory system	a toxic gas that is inhaled or absorbed through the skin and has harmful effects on the nervous and respiratory system