Exhibiting low intelligence, as if having only half a brain.

Alternative form of birdbrained

(colloquial) Idiotic

Muddled in thought or mind; foolish; stupid.

Alternative spelling of scatterbrained

Synonym of beef-witted (“stupid, dull”)

(of an animal) Having a brain which is naturally smooth in appearance. / (of a human) Lissencephalic; having a brain which lacks convolutions due to malformation.

(informal, derogatory) Extremely stupid

Empty-headed; foolish.

Alternative form of lizard brained