lifeguard

noun

1. 1

   A bodyguard or unit of bodyguards, a guard of someone's (especially a king's) life or person.

2. 2

   An attendant, usually an expert swimmer, employed to save swimmers in trouble or near drowning at a body of water.

3. 3

   A lifesaver.

4. 4

   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.