back talk vs riposte

back talk and riposte both are nouns.

Word	Noun	Adjective	Verb	Adverb
back talk	Yes	No	No	No
riposte	Yes	No	Yes	No

As nouns, riposte is a hypernym of back talk; that is, riposte is a word with a broader meaning than back talk:

back talk: an impudent or insolent rejoinder
riposte: a quick reply to a question or remark (especially a witty or critical one)

Other hypernyms of back talk include comeback, counter, rejoinder, replication, retort, return.

back talk (noun)	riposte (noun)
an impudent or insolent rejoinder	(fencing) a counterattack made immediately after successfully parrying the opponents lunge
	a quick reply to a question or remark (especially a witty or critical one)

back talk (verb)	riposte (verb)
	answer back
	make a return thrust