The Collaborative International Dictionary of English v.0.48:

Stripling \Strip"ling\, n. [Dim. of strip; as if a small strip
   from the main stock or steam.]
   A youth in the state of adolescence, or just passing from
   boyhood to manhood; a lad.
   [1913 Webster]

         Inquire thou whose son the stripling is. --1 Sam. xvii.
                                                  56.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "stripling":
   Young Turk, adolescent, arriviste, baby, boy, bright young man,
   comer, fledgling, hobbledehoy, hopeful, infant, junior, juvenal,
   juvenile, lad, laddie, minor, modern, modern generation,
   modern man, modernist, modernizer, neologism, neologist, neology,
   neonate, neoteric, neoterism, neoterist, new generation, new man,
   nouveau riche, novus homo, parvenu, pubescent, rising generation,
   sapling, schoolboy, slip, son, sprig, tad, teenager, teener,
   teenybopper, upstart, young hopeful, young man, young person,
   younger, youngest, youngling, youngster, youth