Other forms: grumpinesses
Grumpiness is a characteristic of being irritable and crabby. The constant grumpiness of your older brother makes him no fun to be with — not even at Disneyland.
Some grumpiness is fleeting, like your grumpiness on a day when nothing seemed to go right: you overslept, you missed the bus, you had to take a pop quiz, and your soccer game was rained out. That could put anyone into a state of grumpiness. In other cases, grumpiness is a disposition, an inherent personality trait: "Your cat is beautiful, but his grumpiness makes it terrifying to pet him for fear of getting scratched!"