idle (adj.)

Old English idel "empty, void; vain; worthless, useless," from Proto-West Germanic *idla- (source also of Old Saxon idal, Old Frisian idel "empty, worthless," Old Dutch idil, Old High German ital, German eitel "vain, useless, mere, pure"), a word of unknown origin.

Subsequent developments are peculiar to English: sense "not employed, not doing work" was in late Old English in reference to persons; from 1520s of things; from 1805 of machinery. Meaning "lazy, slothful" is from c. 1300. In Elizabethan English it also could mean "foolish, delirious, wandering in the mind." Idle threats preserves original sense.

idle (v.)

late 15c., "make vain or worthless" (trans.), from idle (adj.). Meaning "spend or waste (time)" is from 1650s. Meaning "cause to be idle" is from 1788. Intrans. sense of "run slowly and steadily without transmitting power" (as a motor) first recorded 1916. Related: Idled; idling. As a noun, 1630s of persons, 1939 of an engine setting.

updated on July 27, 2018

Definitions of idle from WordNet
idle (adj.)
not in active use;
idle hands
the machinery sat idle during the strike
Synonyms: unused
idle (adj.)
not in action or at work;
idle drifters
the idle rich
an idle laborer
an idle mind
idle (adj.)
without a basis in reason or fact;
idle fears
idle (adj.)
silly or trivial;
idle pleasure
light idle chatter
Synonyms: light
idle (adj.)
lacking a sense of restraint or responsibility;
idle talk
Synonyms: loose
idle (adj.)
not yielding a return;
idle funds
Synonyms: dead
idle (adj.)
not having a job;
idle carpenters
Synonyms: jobless / out of work
idle (v.)
run disconnected or idle;
Synonyms: tick over
idle (v.)
be idle; exist in a changeless situation;
Synonyms: laze / slug / stagnate
idle (n.)
the state of an engine or other mechanism that is idling;
the car engine was running at idle
From, not affiliated with etymonline.