a reply or response to a question or remark, esp a quick witty one; retort
2.
(law) (in pleading) the answer made by a defendant to the claimant's reply
Word Origin
C15: from Old French rejoindre to rejoin²
Word Origin and History for rejoinder
n.
mid-15c., from Middle French noun use of rejoindre (see rejoin (v.2)). Originally "defendant's answer to the replication" (the fourth stage in the pleadings in an action at common law). For noun use of infinitive in French law terms, cf. waiver.