idle money noun (economics)

That part of the total money supply that is neither being used to finance current transactions nor being lent out on the money market

idle pulley noun

A pulley which rotates freely and guides, or controls the tension of, a belt (also iˈdler)

idle time noun

A period or periods when a machine, eg a computer, is able to function properly but is not being used for productive work

idle wheel noun

A wheel placed between two others for transferring the motion from one to the other without changing the direction (also iˈdler)

idle worms plural noun (informal)

Worms once jocularly supposed to be bred in the fingers of lazy maidens