retort vs rejoin

retort is a noun but rejoin is not a noun.

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

As verbs, retort and rejoin are synonyms defined as:

Other synonyms of retort include come back, repay, return, riposte.

retort (noun)	rejoin (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)

retort (verb)	rejoin (verb)
answer back	answer back
	join again