outhouse rat

As in "crazy as a..." Indicates a persons mental health...or rather the complete and total lack thereof. Like shithouse rat, only more pc for use in mixed or questionable company wherein one might become offended.

Person 1: What did you do that for?
Person 2: Don't mind me, I'm just crazy as an outhouse rat.

outhouse rat by ElKrampo7 May 22, 2006