rejoin vs riposte

rejoin is not a noun while riposte is a noun.

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

As verbs, rejoin and riposte are synonyms defined as:

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

rejoin (noun)	riposte (noun)
	(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)

rejoin (verb)	riposte (verb)
answer back	answer back
join again	make a return thrust