discontented
brassed off (Brit. slang) cheesed off (Brit. slang) complaining, disaffected, disgruntled, displeased, dissatisfied, exasperated, fed up, fretful, miserable, pissed off (taboo slang) unhappy, vexed, with a chip on one's shoulder (informal)
Antonyms
cheerful, content, contented, happy, pleased, satisfied