What is tempo in chess?

Answer 1

A stalling move which attacks another piece or puts the king in check

Tempo in Chess is similar to music tempo. a strong example of tempo is if you take your queen out too early, you can spend the next six moves trying to save her the whole time the opponent is advancing troops forward, claiming more land. In the end, though you've moved over and over and over you haven't moved forward, you haven't made progress. Just to catch up youd need that six moves now just to be even with your opponents pace and advancement.