lifesaver

/ˈlaɪfˌseɪvə/

Etymology

From life + saver.

noun

  1. Someone or something that saves lives.; A lifeguard or other rescuer.“My dad loves his job as a surf lifesaver.”
  2. Someone or something that saves lives.; A life buoy.“They threw him a lifesaver and then hauled him up onto the boat.”
  3. Someone or something that saves lives.; Any lifesaving tool or item of supplies.“When I got lost in the woods, my Swiss Army knife was a lifesaver.”
  4. Someone or something that is very useful or helpful.“Thank you so much for fixing my car; you're a real lifesaver!”