What is the meaning of Idler?

One who idles; one who spends his or her time in inaction.

One who idles; a lazy person; a sluggard.

Any member of a ship's crew who is not required to keep the night-watch.

A mechanical device such as a pulley or wheel that does not transmit power through its own axle, but forms part of a gear train, supports a moving belt, etc.

comparative form of idle: more idle

Source: wiktionary.org