sooty (adj.)

"black substance or deposit formed by burning fuel and rising or falling in fine particles," Old English sõt "soot," from Proto-Germanic *sotam "soot" (source also of Old Norse sot, Old Dutch soet, North Frisian sutt), literally "what settles," from PIE *sodo- (source also of Old Church Slavonic sažda, Lithuanian suodžiai, Old Irish suide, Breton huzel "soot"), a suffixed form of root *sed- (1) "to sit." Related: Sootflake.

adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.