Semi-dumb

Someone who is genuinely smart, but always acts like he has less IQ points than his pet rock

Peter: oh yeah, well if f(x) = 2x2 + 4x - 5; then a = 2, b = 4, c = -5.
Jeff: shit you smart
Peter: wait are bees real
Jeff: are you actually braindead
Marcus: nah hes just semi-dumb