in a way that shows irritation, ill humor, or gloom; morosely: In the next room, an embittered, lonely man sits sullenly. with a gloomy or dismal sound: The door thudded sullenly behind her.

What does sullenly mean?

1a : gloomily or resentfully silent or repressed a sullen crowd. b : suggesting a sullen state : lowering a sullen countenance. 2 : dull or somber in sound or color.

Where did the word sullenly come from?

sullen (adj.)

1570s, alteration of Middle English soleyn "unique, singular," from Anglo-French *solein, formed on the pattern of Old French solain "lonely," from soul "single," from Latin solus "by oneself, alone" (see sole (adj.)).