When you get really drunk all night long, get very little sleep, wake up and keep drinking. By the time noon hits you are completely trashed more than you were the night before, and in the middle of a grossover. Like a hangover, only gross.
Wally: I've been drinking all night. I had a 4 hour nap and then started drinking again. Now I can't see straight.
Rory: Well buddy, that's not a hangover. That's a grossover.