(1):

(a.) Absurd; ridiculous; despicable; contemptible.

(2):

(a.) Such as a fool would do; proceeding from weakness of mind or silliness; exhibiting a want of judgment or discretion; as, a foolish act.

(3):

(a.) Marked with, or exhibiting, folly; void of understanding; weak in intellect; without judgment or discretion; silly; unwise.