Definitions

1. noun

A person who whistles, especially as a means of signaling or communicating.

“The whistler on the train warned the passengers of the approaching station.”

2. noun

A person or thing that produces a high-pitched whistling sound.

“The whistler on the kettle was very loud and annoying.”

3. noun

A person who climbs mountains, especially a mountain peak, at dawn to watch the sunrise.

“The whistler was a famous mountaineer who climbed many peaks around the world.”

4. verb

To signal or communicate by whistling.

“The coach whistled to signal the end of practice.”