lifeguard

/ˈlaɪfˌɡɑɹd/

Etymology

From life + guard, calque of Dutch lijfgarde, where life has the sense of Dutch lijf (“body”) (hence literally “bodyguard”). Compare German Leibgarde (“bodyguard”), Danish livgarde (“bodyguard”), Swedish livgarde (“bodyguard”). Compare also Old English līfweard (“guardian of life”).

noun

A lifesaver: a rescuer, usually an expert swimmer, employed to save swimmers in trouble or near drowning at a body of water.“It's also generally wise to recruit lifeguards to ensure visitor safety, as bathers can panic in the water and require assistance.”
A bodyguard or unit of bodyguards, a guard of someone's (especially a king's) life or person.“"The people's love is the king's lifeguard."”
A sturdy metal bracket fixed in front of each of the leading wheels of a train to deflect small objects away from the wheels to prevent derailment.“It also looked at what effect stronger lifeguards might have had. They protect the leading wheels from small obstacles and in modern trains have coped with hitting landslip debris.”