I recently happened upon a comment (not on HN) that seemed to treat 'zugzwang' as a synonym for 'deadlock'. Possibly because 'zugzwang' sounds really cool and makes your inner voice sound intelligent to your inner ear.
More accurately, it’s being forced to move a specific piece despite disadvantages, because not moving it would result in an even worse outcome — as opposed to moving a different piece that you’d otherwise prefer to move. So it means being forced to move that first piece instead of not moving it (instead of moving a different piece).
And that’s the generalized meaning in German, being forced to act with respect to a specific thing, where you’d normally prefer to keep it in its current state.
You run out of time on your clock. If you press your clock without moving, the opponent will alert the referee to sort you out. And if you play without a clock, your opponent will get annoyed at you taking forever to move.