A sexy young (usually underage) girl. Typically dirty old men like the young ones.
-"Miley is hot! She really is a nymphette and you know how I roll; if there is grass on the field, play ball!"
-"I am going to have to register as a sex offender because I have a problem with these nymphettes."
-"I can't search for nymphette at work anymore because they caught me last week and I already have 2 warnings."