Loss of tempo

In chess, a tempo is one move, not a second on the clock. A player loses a tempo when a piece needs an extra move to achieve what a more direct route could have accomplished, or when a threat forces a retreat while the opponent improves.

In the opening, moving the same piece repeatedly often loses time while other pieces remain on their starting squares. An early queen, for example, may be attacked by a bishop or knight. The queen must move again, while the opponent brings that piece to a useful square with a threat and improves while forcing the retreat.

The expression always depends on the objective. Moving a piece twice is not automatically wrong: the move may win material, stop a threat, or create a more important attack. Opening theory, the accumulated knowledge about early moves and their plans, compares the sequence with realistic alternatives rather than applying an absolute prohibition.

Deliberately losing a tempo

In some endings, losing a tempo on purpose is useful. A player may take a longer route or make a waiting move so that the opponent must move in an unfavorable position. This technique is common in zugzwang, where having the move is a disadvantage.

The phrase can therefore carry two meanings according to context. In opening criticism it usually identifies inefficiency; in endgame technique it may describe a precise maneuver that hands over the move at the right moment.