exp.

1. to raise one's hand
2. idiomatic to surrender (usu. 手を上げる)
3. to raise one's hand to someone (as a threat to strike) (usu. 手を上げる)
4. idiomatic to become better (at something); to improve (usu. 手を上げる)
5. idiomatic to throw one's hat in the ring; to volunteer; to indicate one intends to participate; to raise one's hand (usu. 手を挙げる)