NOT WORKING › not working or being used: The factory has stood idle for over a year.
NOT SERIOUS [always before noun] › not serious or having no real purpose: idle gossip This is no idle threat. LAZY › lazy and not willing to work: He knows what has to be done, he's just bone idle (= extremely lazy).
idleness noun [U] idly adverb › We cannot stand idly by (= not do anything) and let this plan go ahead.