petulant
PECH-uh-luntadjMeaning childishly sulky and bad-tempered
Memory hook PET-ulant: sulks like a spoiled PET. When he doesn’t get a second treat, Biscuit the puppy turns his back and sulks. What a petulant pet!
Told to turn off his game, the petulant boy pouted, sulked and stomped up the stairs.
In context Instead of congratulating the winner, the petulant runner-up stomped off the court, refused to shake hands and sulked on the bus all the way home.
Similar sulky, peevish, cranky, testy
Opposite good-humored, cheerful, easygoing