Collins COBUILD Advanced Learner's English Dictionary - lifesaver

(lifesavers) If you say that something is a lifesaver, you mean that it helps people in a very important way, often in a way that is important to their health. The cervical smear test is a lifesaver. N-COUNT LIFE-SAVING 1. A life-saving drug, operation, or action is one that saves someone’s life or is likely to save their life. ...life-saving drugs such as antibiotics... She decided her child should go to America for life-saving treatment. ADJ: usu ADJ n 2. You use life-saving to refer to the skills and activities connected with rescuing people, especially people who are drowning. N-UNCOUNT