adj. Chiefly British Slang. Insane; mad. [Probably from cracker, breakdown.]

What does having crackers mean?

If you say that someone or something is a cracker, you like and admire them very much. [British, informal] She’s a cracker.

What's another word for cracker?

• biscuit.
• cookie.
• pretzel.
• bun.
• hardtack.
• rusk.
• saltine.