Also known as Jail-Bait for Jail-Bait, is a word termed by UMAMI as a person who is usually under the age of 13. Jail-Bait = too young for 18+
JB for JB = Too young for 16+
16yrold1: Did you see that HOT girl?!?
16yrold2: Dude, she was major JB for JB... YUCK