Definitions

1. noun

a person employed to supervise and rescue people in or near the water, especially at a beach or swimming pool.

“The lifeguard blew his whistle to signal the start of the swim competition.”

2. verb

to watch over or supervise someone or something, especially in a situation where there is a risk of injury or danger.

“The coach had to lifeguard her player during the intense tennis match.”

3. noun

a device or system that monitors and controls a situation, especially a system of alarms and warning signals.

“The lifeguard system sounded the alarm when it detected a person struggling in the water.”