Someone who is completely outside of their damn minds and yet also full of crap.
Could also be a very hard solid and almost walnut shaped piece of poop, the kind that hurts when it comes out and causes the wet cheeks affect (when toilet water and/or piss splashes onto your rear from the impact of the solid fecies)
"That turd nut over there just told me that she saw a special on c-span about Canada, USA, and Mexico becoming one country."
"I am having the worst night possible! I was on a date, hadn't had my benafiber and I passed a huge turd nut at the restaurant and when I went to wipe my wet ass there was no toilet paper so I had this huge yellow ring on the seat of my white skirt the rest of the night"