tit for tat

noun

1. with an equivalent given in retaliation, as a blow for a blow, repartee, etc.: He answered their insults tit for tat.

noun

1. an equivalent given in return or retaliation; blow for blow

1550s, possibly an alteration of tip for tap “blow for blow,” from tip (v.3) “tap” + tap “touch lightly.” Perhaps infl. by tit (n.2). Giving back exactly what one receives: “If you hit me, I’ll do the same to you; it’s tit for tat.” Repayment in kind, retaliation, as in If he won’t help with the beach clean-up, I won’t run a booth at the bake sale; that’s tit for tat. This term is believed to be a corruption of tip for tap, which meant “a blow for a blow.” Its current form dates from the mid-1500s.