reciprocate

Etymology

From Latin recīprocō (“to move back and forth”), possibly from a phrase such as reque proque (“back and forth”), from re- (“back”), prō (“forwards”) and -que (“and”). Compare reciprocal.

verb

1. (transitive) To exchange two things, with both parties giving one thing and taking another thing.
2. (transitive) To give something else in response (where the "thing" may also be abstract, a feeling or action) To make a reciprocal gift.
   I gave them apples from my tree; they reciprocated with a pie and some apple jelly.
   Nugget appreciates the generosity! Nugget will reciprocate with a Monstermon card! 2019, Con Man Games, SmashGames, quoting Nugget, Kindergarten 2, SmashGames
3. (intransitive) To move backwards and forwards, like a piston.
   A reciprocating engine.
   One brawny smith the puffing bellows plies, / And draws and blows reciprocating air.
4. (intransitive) To counter, retort or retaliate.