- 1bad-tempered and not speaking, either on a particular occasion or because it is part of your character Bob looked pale and sullen. She gave him a sullen glare. sullen teenagers
- 2(literary) (of the sky or weather) dark and unpleasant a sullen gray sky
adverb
NAmE//ˈsʌlənnəs//
noun [uncountable]See sullen in the Oxford Advanced Learner's DictionaryCheck pronunciation: sullen