lifeguard

Meanings

1. A lifesaver: a rescuer, usually an expert swimmer, employed to save swimmers in trouble or near drowning at a body of water.
2. A bodyguard or unit of bodyguards, a guard of someone's (especially a king's) life or person.
3. 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.

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”).