when one's bra is too small, and one or both boobs are poking over the top of the cup. there are varying degrees of overboob; and when a severe case affects both boobs, it is called quadriboob.
I haven't worn this bra in a while, I must've outgrown it... I've had overboob all day long and no one told me!
by the Cheshire Kat February 09, 2007