Reciprocate, retaliate, requite, return can mean to give back usually in kind or in quantity.
Reciprocate may imply a mutual, equivalent, or roughly equivalent, exchange or a paying back of what one has received. The connotations of alternating movements and of correspondence between what is interchanged are usually stressed.
Retaliate denotes chiefly a paying back of an injury and usually implies return in exact kind, often vengefully.
Requite can imply simply a paying back, usually reciprocally, but additionally it can imply a paying back according to what one construes as the merits of the case and then need not imply satisfaction to both parties concerned.
Return (see also RETURN ) does not emphasize the idea of interchanging so strong in reciprocate but rather that of paying back whatever has been given, usually in kind but sometimes by way of contrast.