Tu quoque [a] is a discussion technique that intends to discredit the opponent's argument by attacking the opponent's own personal behavior and actions as being inconsistent with their argument, so that the opponent appears hypocritical. This specious reasoning is a special type of ad hominem attack. The Oxford English Dictionary cites John Cooke's 1614 stage play The Cittie Gallant as the earliest known use of the term in the English language. [1]
The (fallacious) tu quoque argument follows the template (i.e. pattern): [2]
For example:
Person A makes a statement, and Person B reasons that because Person A is being hypocritical, their statement is false.
A similar concept in politics is that of whataboutism; raising a counteraccusation, often in the form of a larger but unrelated issue. In the Soviet Union in the 1930s, the phrase "and you are lynching Negroes" was often raised against the United States.