angry and unwilling to smile or be pleasant to people愠怒的;闷闷不乐的,绷着脸的
His daughters stared back at him with an expression of sullen resentment.他的几个女儿也满脸愠怒地狠狠回瞪他。
literary She looked up at the sullen (= dark and unpleasant) sky and shuddered.她抬头看了看阴沉沉的天空,不由打了个冷颤。