sullen

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Showing a brooding ill humor or silent resentment; morose or sulky.
• adjective Gloomy or somber in tone, color, or portent.
• adjective Sluggish; slow.

from The Century Dictionary.

• To make sullen, morose, or sulky.
• Being alone; solitary; lonely; hence, single; unmarried.
• Being but one; unique; hence, rare; remarkable.
• Remaining alone through ill humor; unsociable; silent and cross; sulky; morose; glum.
• Gloomy; dismal; somber.
• Sad; sorrowful; melancholy.
• Slow-moving; sluggish; dull: as, a sullen pace.
• Malignant; unpropitious; foreboding ill; baleful.
• Synonyms Gloomy, Sullen, Sulky, Morose, Splenetic. These words are arranged in the order of their intensity and of their degrees of activity toward others. Gloomy has the figurative suggestion of physical gloom or darkness: the gloomy man has little brightness in his mind, or he sees little light ahead. The sullen man is silent because he is sluggishly angry and somewhat bitter, and he repels friendly advances by silence and a lowering aspect rather than by words. The sulky person persists in being sullen beyond all reason and for mere whim: the young are often sulky. In the morose man there is an element of hate, and he meets advances with rudeness or cruel words: the young have rarely development of character enough to be morose. The splenetic man is sulky and peevish, with frequent outbursts of irritation venting itself upon persons or things. Any of these words may indicate either a temporary mood or a strong tendency of nature.
• noun A solitary person; a recluse.
• noun plural Sullen feelings; sulks; sullenness.
• noun A meal for one person.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To make sullen or sluggish.
• noun obsolete One who is solitary, or lives alone; a hermit.
• noun obsolete Sullen feelings or manners; sulks; moroseness.
• adjective obsolete Lonely; solitary; desolate.
• adjective Gloomy; dismal; foreboding.
• adjective Mischievous; malignant; unpropitious.
• adjective Gloomily angry and silent; cross; sour; affected with ill humor; morose.
• adjective Obstinate; intractable.
• adjective Heavy; dull; sluggish.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Having a brooding ill temper; sulky.
• adjective Dismal; somber.
• adjective Sluggish; slow.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective showing a brooding ill humor
• adjective darkened by clouds