"trivial, idle, or worthless talk," 1550s, a varied reduplication of prattle. Also from 1550s as a verb.
"a leisurely stroll, a ramble," 1828, from saunter (v.). Earlier it meant "idle occupation, diversion" (1728); "leisurely, careless way of walking" (1712).
Meaning "conceited, elated with a high opinion of oneself" first recorded 1690s in English; earlier "silly, idle, foolish" (late 14c.). Phrase in vain "to no effect" (c. 1300, after Latin in vanum) preserves the original sense. Related: Vainly; vainness. Compare also vainglory.
mid-13c., "a run of quick, shrill sounds," originally of birds, from chatter (v.). Meaning "idle or foolish talk" is by 1831.
1794, "unfruitful, futile," from Latin otiosus "having leisure or ease, unoccupied, idle, not busy" (source of French oiseux, Spanish ocioso, Italian otioso), from otium "leisure, free time, freedom from business," a word of unknown origin. Meaning "at leisure, idle" is recorded from 1850. Compare Latin phrase otium cum dignitate "leisure with dignity." Earlier adjective in English was otious "at ease" (1610s), and Middle English had noun otiosity (late 15c.).