Nouns

(n)idlethe state of an engine or other mechanism that is idling“the car engine was running at idle”

Verbs

(v)idle, tick overrun disconnected or idle“the engine is idling”
(v)idle, laze, slug, stagnatebe idle; exist in a changeless situation“The old man sat and stagnated on his porch”, “He slugged in bed all morning”

Adjectives

(a)idlenot in action or at work“an idle laborer”, “idle drifters”, “the idle rich”, “an idle mind”
(s)baseless, groundless, idle, unfounded, unwarranted, wildwithout a basis in reason or fact“baseless gossip”, “the allegations proved groundless”, “idle fears”, “unfounded suspicions”, “unwarranted jealousy”
(s)idle, unusednot in active use“the machinery sat idle during the strike”, “idle hands”
(s)idle, lightsilly or trivial“idle pleasure”, “light banter”, “light idle chatter”
(s)idle, looselacking a sense of restraint or responsibility“idle talk”, “a loose tongue”
(s)dead, idlenot yielding a return“dead capital”, “idle funds”
(s)idle, jobless, out of worknot having a job“idle carpenters”, “jobless transients”, “many people in the area were out of work”