Definition of "idler"

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

One who idles; a lazy person; a sluggard.  examples

(nautical, dated) Any member of a ship's crew who is not required to keep the night-watch.  examples

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.  quotations  examples

comparative form of idle: more idle  examples