Reserve the adjective vapid for the airhead in your office that brings nothing to the table, except maybe the doughnuts. (And be careful to mutter it behind her back; it's much too vicious for a casual dig.)
Vapid means "dull" or "uninspiring": "We prefer not to consider the shockingly vapid and primitive comments uttered by athletes in postcontest interviews," David Foster Wallace wrote. The word was originally used in English in a much more literal sense, describing beverages that lacked flavor. It comes from the Latin word vapidus, literally "having exhaled its vapor."
