sarcastic vs mordant

sarcastic is not a noun while mordant is a noun.

Word	Noun	Adjective	Verb	Adverb
sarcastic	No	Yes	No	No
mordant	Yes	Yes	No	No

sarcastic (noun)	mordant (noun)
	a substance used to treat leather or other materials before dyeing; aids in dyeing process

sarcastic (adjective)	mordant (adjective)
expressing or expressive of ridicule that wounds	of a substance, especially a strong acid; capable of destroying or eating away by chemical action
	harshly ironic or sinister