CN gas vs tear gas

CN gas and tear gas both are nouns.

Word	Noun	Adjective	Verb	Adverb
CN gas	Yes	No	No	No
tear gas	Yes	No	No	No

As nouns, tear gas is a hypernym of CN gas; that is, tear gas is a word with a broader meaning than CN gas:

CN gas: a tear gas that is weaker than CS gas but lasts longer
tear gas: a gas that makes the eyes fill with tears but does not damage them; used in dispersing crowds

Other hypernyms of CN gas include lachrymator, lacrimator, teargas.

CN gas (noun)	tear gas (noun)
a tear gas that is weaker than CS gas but lasts longer	a gas that makes the eyes fill with tears but does not damage them; used in dispersing crowds