Merriam-Webster Online Dictionary
adolescent (noun)one that is in the state of - adolescence
1.
of, relating to, or being in - adolescence
2.
emotionally or intellectually immature
Merriam-Webster Online Thesaurus
adolescent (adjective)1.
being in the early stage of life, growth, or development
SYNONIMS:
adolescent, immature, juvenile, youngish, youthfulRELATED WORDS:
ephebic, minor, preteen, subadult, teenage ( teenaged), underage; embryonic, emergent; callow, green, inexperienced, puerile, raw; babyish, childish, childlike, infantile, infantine, kiddish; undeveloped, unfinished, unfledged, unformed, unripe, unripened; blooming, blossoming, burgeoning, flourishing, floweringNEAR ANTONYMS:
aged, aging ( ageing), ancient, elderly, geriatric, long-lived, old, older, oldish, senescent, senior; full-blown, full-fledged; golden, mellow, ripe, ripened; middle-aged; anile, decrepit, doddering, over-the-hill, senile, spavined, tottery2.
having or showing the annoying qualities (as silliness) associated with children
SYNONIMS:
adolescent, babyish, immature, infantile, jejune, juvenile, kiddish, puerileRELATED WORDS:
boyish, brattish, bratty, girlie ( girly), girlish; childlike, innocent, naive ( naïve), simple, simplistic, unsophisticatedNEAR ANTONYMS:
unchildlike; cosmopolitan, experienced, knowing, smart, sophisticated, worldly, worldly-wise3.
lacking in adult experience or maturity
SYNONIMS:
adolescent, green, immature, inexperienced, juvenile, puerile, raw, unfledged, unformed, unripe, unripenedRELATED WORDS:
babyish, childish, infantile, infantilized, infantine; boyish, girlish, juvenescent, kiddish, young, youngish, youthful; maidenly, virginal; ingenuous, innocent, naive ( naïve), tender; unknowing, unseasoned, unsophisticated, untrained, untriedNEAR ANTONYMS:
advanced, precocious; knowing, savvy, sophisticated, worldly, worldly-wise