The state of one's digestive system after a night of drinking lots of beer. It is a prolonged period of beer shits, and is characterized by repeated heavy shits, that take forever to come out, and leave greasy streaks on the bottom of the toilet.
I got hammered last night, and I've had the grumps all morning.
Man, somebody must have the grumps; I can smell it from here, and the toilet is shit-stained.
I had the grumps this morning, and I feel about 5 pounds lighter now.