A half erect penis, either a result of being only partialy aroused, or being paranoid of being caught.
"So then she took off her pants and was about to start riding me, but then Steve came home, and we had to stop all of a sudden. After he left, we tried to get back into it, but my wang was freaked out, and I couldn't get it up past half-chub, so we just gave up."
by the mecca November 03, 2006
Half chub is a conditon that effects the male population. Symptoms are mainly a slightly erect penis, not a full boner.
Oh My Jon has a half chub! What the heck is wrong with him i thought he would be the future bussiness leader of america, but the half chub interupted!
by Parkizzle September 02, 2005