Someone who isn't on the "A-Team". Someone who is less than you; an asshole, idiot, loser, microphone abuser.
Hey bro's! Look at those B-Teamers over there. They're drinking cheap beer. Lets go fight them.
adj., 1. characteristic of one who might possibly play on a b-team;
2. quality of being on a b-team
a) Dude, you missed practice last week? That's pretty fuckin' b-teamer of you.
b) That guy has b-teamer skillz.
c) I didn't make the varsity squad cuz I'm so b-teamer its pathetic.