retort vs back talk

retort and back talk both are nouns.

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

As nouns, back talk is a hyponym of retort; that is, back talk is a word with a more specific, narrower meaning than retort:

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

Other hyponyms of retort include backtalk, lip, mouth, sass, sassing.

retort (noun)	back talk (noun)
a vessel where substances are distilled or decomposed by heat	an impudent or insolent rejoinder
a quick reply to a question or remark (especially a witty or critical one)

retort (verb)	back talk (verb)
answer back