Lifesaver (noun)

A person or thing that saves someone's life or solves a difficult problem.

Origin:

Compound word from "life" and "saver".

Examples:

1. The rescue team was a lifesaver.
2. The medication was a lifesaver for the patient.
3. The rope was a lifesaver for the climber.
4. The device was a lifesaver for the drowning person.
5. The idea was a lifesaver for the company.