The Collaborative International Dictionary of English v.0.48:
Soft-headed \Soft"-head`ed\, a. Weak in intellect. [1913 Webster]WordNet (r) 3.0 (2006):
softheaded adj 1: foolish; totally unsound; "a crazy scheme"; "half-baked ideas"; "a screwball proposal without a prayer of working" [syn: crazy, half-baked, screwball, softheaded]