In French, « joindre » means "to join". What semantic notions underlie « joindre » with the 2020 English "rejoin", which means to riposte? How did *rejoindre* shift to signify the 2020 English "rejoin"? Clearly, "to rejoin" and "to riposte" don't mean the same actions!
[This French Stack Exchange comment](https://french.stackexchange.com/questions/43121/comment-re-joindre-glissent-t-ils-s%c3%a9mantiquement-pour-signifier-r%c3%a9to#comment87380_43121) vouches that Etymonline below is wrong, because *rejoindre* has never meant "to answer a legal charge".
###[rejoin (v.2)](https://www.etymonline.com/word/rejoin)
> "to answer," mid-15c., legal term,
from Middle French *rejoin-*, stem of *rejoindre* "to answer to a legal charge,"
from Old French *re-* "back" (see [re-](https://www.etymonline.com/word/re-?ref=etymonline_crossreference)) + *joindre* "to join, connect, unite,"
from Latin *iungere* "to join together, unite, yoke," from nasalized form of PIE root [\*yeug-](https://www.etymonline.com/word/*yeug-?ref=etymonline_crossreference) "to join." General (non-legal) meaning first recorded 1630s.
###[rejoinder (n.)](https://www.etymonline.com/word/rejoinder)
> mid-15c., from Middle French noun use of *rejoindre* "to answer to a legal charge" (see [rejoin](https://www.etymonline.com/word/rejoin?ref=etymonline_crossreference#etymonline_v_10359) (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, see [waiver](https://www.etymonline.com/word/waiver?ref=etymonline_crossreference).
