Someone slow, dimwitted or stupid - another way of saying "Not the sharpest knife in the drawer". Also, someone who stands out in a crowd as being particularly unintelligent.
Marisa: Why does Eric even bother talking in class - he has no idea what he's talking about.
Michael: What do you expect? I mean he's not the brightest bulb in the chandelier!
Michael: What do you expect? I mean he's not the brightest bulb in the chandelier!
by SpencerDuhm March 15, 2009