Pronunciation: (sul'un), [key]
1. showing irritation or ill humor by a gloomy silence or reserve.
2. persistently and silently ill-humored; morose.
3. indicative of gloomy ill humor.
4. gloomy or dismal, as weather or a sound.
5. sluggish, as a stream.
6. Obs.malignant, as planets or influences.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.