Her parents' divorce greatly affected her and caused her to become sullen, withdrawn, and isolated at school.
en.wikipedia.org It was a nickname given to him by his classmates due to his sullen attitude towards school.
en.wikipedia.org He is generally the most likely to experience extremes of emotion, and is usually depicted as being aggressive, sullen, maddened, and rebellious.
en.wikipedia.org The man's condition, which in earlier works might have been characterised by hope or helplessness, has turned to sullen rage.
en.wikipedia.org The term has the meaning of one being crestfallen, depressed, despondent, downcast, gloomy, sullen and evidently frowning, scowling.
en.wikipedia.org