a. Pizza with spaghetti on the side
b. Pizza with spaghetti sauce on top
c. Pizza with spaghetti AND sauce on top
2. (noun) Any bad decision which is obviously bad to everyone else but you. May also be used to describe a serious mistake you've made.
Fool: May I please have some delicious pizzaghetti, with some bruschetta on the side ?
Wise Man: Dude, that's a textbook pizzaghetti !
2. Fool: Tonight, I'm getting wasted !
Wise Man: The drunker you get, the more pizzaghettis you'll make.
The next morning.
Fool: I can't believe I've slept with that chick...
Wise Man: She's so ugly ! What a pizzaghetti !