Cat and mouse, often expressed as cat-and-mouse game, is an English-language idiom that means "a contrived action involving constant pursuit, near captures, and repeated escapes." The "cat" is unable to secure a definitive victory over the "mouse", who, despite not being able to defeat the cat, is able to avoid capture. In extreme cases, the idiom may imply that the contest is never-ending. The term is derived from the hunting behavior of domestic cats, which often appear to "play" with prey by releasing it after capture.

In colloquial usage, it has often been generalized to mean the advantage constantly shifts between the contestants, leading to an impasse or de facto stalemate.^{[citation needed]} Furthermore, the term has been used to refer to the game hide-and-seek.^{[citation needed]}