A stupid or inept person.

plural of half-wit

Clever, keen of intellect, swift of thought.

Lacking a keen or swift intellect, not too bright or not too swift.

Quickwitted.

Alternative form of blood-wite

Having a low intelligence; dim-witted.

(chiefly Britain) The limit of one's sanity or mental capacity; the point of desperation.

(rare, idiomatic) Thinking of an idea or course of action too late to use it effectively, or the tendency to do so.

Having a dull, blunt wit or mind; unintelligent.