idle vs otiose

idle is a noun but otiose is not a noun.

Word	Noun	Adjective	Verb	Adverb
idle	Yes	Yes	Yes	No
otiose	No	Yes	No	No

idle (noun)	otiose (noun)
the state of an engine or other mechanism that is idling

idle (adjective)	otiose (adjective)
not in action or at work	disinclined to work or exertion
silly or trivial	producing no result or effect
not in active use	serving no useful purpose; having no excuse for being
lacking a sense of restraint or responsibility
not having a job
not yielding a return
without a basis in reason or fact

idle (verb)	otiose (verb)
run disconnected or idle
be idle; exist in a changeless situation