Zugzwang

Zugzwang is a German term meaning "compulsion to move". It refers to a situation in chess and other turn-based games where a player is forced to make a move that will significantly weaken their position.

In chess, players are not allowed to "pass" their turn. If it were legal to skip a move, a player in zugzwang would choose to do so to maintain their current defensive setup; however, the obligation to act forces them to create a vulnerability.