How to sign: a person lacking intelligence or common sense
Similiar / Same: simple
Categories: human, mortal, person, somebody, someone, soul
Within this category: airhead, dimwit, dingbat, dumbbell, dunce, fool, idiot, idiot savant, nebbish, nincompoop, scatterbrain, schlemiel, schnook, sheep, space cadet, square, stupid, subnormal, twerp