adj. Before the age at which a person is first capable of sexual reproduction.
adj. Who is not yet capable of sexual reproduction. Immature.
The Century Dictionary and Cyclopedia
Prior to the occurrence of puberty.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. (especially of human beings) at the age immediately before puberty; often marked by accelerated growth
Word Usage
"A few examples: I was pretty stoked when Ugly Betty‘s Henry and Betty separated — a zit-plagued prepubescent is less awkward than that relationship — and didn’t really bat an eyelash when Jack and Kate ended their relationship on Lost."