Teenager :  (noun)

1: a juvenile between the onset of puberty and maturity [syn: adolescent, stripling]

adolescent, baby, boy, fledgling, girl, hopeful, infant, junior, juvenal, juvenile, kid, minor, pubescent, sapling, slip, sprig, stripling, teener, teenybopper, young hopeful, young man, young person, younger, youngest, youngling, youngster, youth,