Lifesaver
01
救命浮輪, ライフセーバー
a life preserver in the form of a ring of buoyant material
02
ライフガード, 救助員
an attendant employed at a beach or pool to protect swimmers from accidents
03
命の恩人, 救世主
something that provides great help in a difficult situation
Informal
例
This portable charger is a lifesaver when my phone dies.
このポータブル充電器は、私の電話が死んだときの命の恩人です。
That coffee was a total lifesaver during the night shift.
夜勤中のあのコーヒーは完全な命の恩人だった。
