respond vs retort

respond is not a noun while retort is a noun.

Word	Noun	Adjective	Verb	Adverb
respond	No	No	Yes	No
retort	Yes	No	Yes	No

As verbs, retort is a hyponym of respond; that is, retort is a word with a more specific, narrower meaning than respond:

Other hyponyms of respond include call back, counter, field, sass, come back, rejoin, repay, return, riposte, bridle.

respond (noun)	retort (noun)
	a vessel where substances are distilled or decomposed by heat
	a quick reply to a question or remark (especially a witty or critical one)

respond (verb)	retort (verb)
show a response or a reaction to something	answer back
respond favorably or as hoped
react verbally