Niffy

Not nifty, but NIFFY. I learned this word while reading after P. G. Wodehouse. The phrase was "a niffy piece of cheese." At first I thought I had read it wrong, because I could see nothing about a piece of cheese that would be described as particularly nifty, but then I looked more closely and saw that there was no "t", but two "f"'s. Niffy is defined as "ill smelling, malodorous, stinky, unpleasant-smelling" - all of which would fit a piece being used as dog food.