life-saver

noun

1. a person who rescues another from danger of death, especially from drowning.
2. a person or thing that saves a person, as from a difficult situation or critical moment: That money was a lifesaver.
3. Chiefly British. a lifeguard.

noun

1. the saver of a person’s life
2. another name for lifeguard
3. informal a person or thing that gives help in time of need