Idling p. pr. & vb. n. : of Idle

Example:
How long can you leave a car Idling before it becomes more economical to turn it off and restart?

Taxonomy
doing nothing, free encyclopedia, In Praise of Idleness, the virtues, dependent, cultural norms, search, lack of motion, energy, describing a person, John Smith, idle person, relative importance, idly, passing, application, tickover, objective statement.

Defination from the web:
idle, it is an objective statement regarding its current state. ... Such a view is reflected in the proverb "an idle mind is the devil's workshop" ... The state of being idle is sometimes even celebrated with a few books on the subject of Idleness. ...