Input Latency

The delay between a player's physical input and the corresponding response appearing on screen. Even milliseconds of latency can affect feel and fairness in fast-paced games.

In games, this means

In fighting games, input latency above 4–6 frames becomes perceptible and ruins the sense of precision. In menu navigation, latency above 100ms makes interfaces feel sluggish. UI responsiveness is part of the UX, not just the game engine.