When someone engages in "tit for tat," it means they respond to an action or behavior with an equivalent action or behavior, typically negative.
For example:
- "After my colleague criticized my work, I couldn't help but give a tit for tat response."
- "In playground squabbles, children often engage in tit for tat exchanges."
Similar expressions include "an eye for an eye," "payback," or "retaliation." These phrases illustrate the idea of responding to someone's actions with similar actions.