1. Foolish, deceitful, bombastic, or arrogant talk. Primarily heard in US. Ah, don't listen to Jem, he's just full of horse pucky.
2. Something that is worthless, terrible, disingenuous, or unfair. Primarily heard in US. This is horse pucky! I'm supposed to be graduating next spring and instead I've got to repeat my senior year! Can you believe this horse pucky? They're trying to charge us double on our insurance just because of that fender bender we had last month!