The American Heritage® Dictionary of the English Language, 4th Edition
adj. Sooty.
adj. Colored by or as if by soot.
the GNU version of the Collaborative International Dictionary of English
adj. Pertaining to soot; sooty; dark; dusky.
adj. Pertaining to smoke; resembling smoke.
The Century Dictionary and Cyclopedia
Pertaining to or having the color of soot; sooty.
Pertaining to smoke; resembling smoke; dusky.
Specifically, in zoöl, and botany, very dark, opaque brown; of the color of soot.
Word Usage
"On my way to trying to find that 'F' word, I learned that "fuliginous" means colored by soot, and the third definition of "flocculus" is a cloudlike mass of gas appearing on the sun's surface."