People sometimes refer to a young man as a stripling when they want to indicate in a slightly humorous way that although he is no longer a boy, he is not yet really a man. a stripling of
A juvenile between the onset of puberty and maturity (syn: adolescent, teenager)
a boy who is almost a young man - sometimes used humorously about a man who is quite old = youth (Probably from STRIP + -ling; from the idea of being thin)