puerile

1 having or showing the annoying qualities (as silliness) associated with children told the teenagers that such puerile behavior would not be tolerated during the ceremony Synonyms adolescent, babyish, immature, infantile, jejune, juvenile, kiddish, childishRelated Words boyish, brattish, bratty, girlie (or girly), girlish; childlike, innocent, naive (or naïve), simple, simplistic, unsophisticatedNear Antonyms unchildlike; cosmopolitan, experienced, knowing, smart, sophisticated, worldly, worldly-wiseAntonyms adult, grown-up, mature

2 lacking in adult experience or maturity allowed the company to be taken over by a bunch of puerile whippersnappers fresh out of business school Synonyms adolescent, green, immature, inexperienced, juvenile, callow, raw, unfledged, unformed, unripe, unripenedRelated Words babyish, childish, infantile, infantilized, infantine; boyish, girlish, juvenescent, kiddish, young, youngish, youthful; maidenly, virginal; ingenuous, innocent, naive (or naïve), tender; unknowing, unseasoned, unsophisticated, untrained, untriedNear Antonyms advanced, precocious; knowing, savvy, sophisticated, worldly, worldly-wiseAntonyms adult, experienced, grown-up, mature, ripe

3 lacking in seriousness or maturity the kind of puerile jokes that teenage moviegoers apparently love Synonyms birdbrained, ditzy (or ditsy), dizzy, featherbrained, flighty, frivolous, frothy, futile, goofy, harebrained, light-headed, light-minded, giddy, scatterbrained, silly, yeastyRelated Words fatuous, foolish, inane, nonsensical, thoughtless, witless; crazy, daffy, daft, fruity; exuberant, flippant, fluttery, giggly, happy, light, lighthearted, playful; sappy, shallow, superficialNear Antonyms grave, melancholy, somber (or sombre), thoughtful; dignified, heavy, no-nonsense, sedate, severe, solemn, staidAntonyms earnest, serious, serious-minded, sober, unfrivolous