(a) Having the manner or ideas of a madman; like a madman in behaviour; appropriate to or befitting a madman. (b) Somewhat mad.

Perhaps: mad, crazy.

Of the brain, mind, etc.: Unsound, impaired, somewhat deranged. Of a person: Unsound in mind, slightly insane, crazy. to be cracked aboutor on, to…

grown crotchety, slightly crazed.

slightly deranged; ‘touched’ in the head (see touch, v. 29b touched, adj. 3).

Slightly mad, crazy, or mentally unsound; a little eccentric. Chiefly in predicative use. Frequently in phrases, as touched in the head, touched in…

Not having all his or her wits; weak-minded; daft.

Somewhat mad.

Somewhat deranged.

Somewhat cracked in intellect; crazy.

to be all there (colloquial): to have all one's faculties or wits about one; to be smart or on the alert; hence, not all there = not quite right…

Displaying erratic behaviour; eccentric. rare.

Mentally deranged to a slight degree; somewhat mad, crazy, or ‘cracked’; = touched, adj. 3.

In colloquial phrase as daft (mad,etc.) as a brush, quite daft or mad; crazy.