re·join 1 
(rĭ-join)
(rĭ-join)v. re·joined, re·join·ing, re·joins
v.tr.
To say in reply, especially in sharp response to a reply.
v.intr.
To reply.
[Middle English rejoinen, from Old French rejoindre, rejoin- : re-, re- + joindre, to join; see JOIN.]