Other forms: sulking, sulks, sulked
To sulk is to go quiet and moody because you did not get your way. Sulk about it, in a sulk, sulking upstairs.
The silence is the point: sulking is a protest made by withdrawal rather than by argument, and it is designed to be noticed. It is used most of children and, unkindly, of adults behaving like them. As a noun, a sulk is the episode itself. Note sulky, which came first — the verb was made backwards from the adjective.
1verbsulkTo go quiet and moody because you did not get your way.
“He sulked in his room because he wasn't allowed to go to the party.”
2nounepisodeSuch an episode.
“She's in a sulk because we ate the last biscuit.”
sulk is a moody withdrawal.
Sulk is a back-formation from sulky, whose own origin is uncertain, possibly from an Old English word for laziness. The adjective came first.
Proto-Indo-European
*selǵ-
Old English
āsolcennys — idleness; slothfulness; sluggishness; laziness
Middle English
*sulke
English, today
sulk
Built from
a back-formation from sulky, of unknown origin. Probably from Middle English sulke, solke (attested in solcenesse (“idleness; laziness”), from Old English āsolcennys (“idleness; slothfulness; sluggishness; laziness”), from āsolcen (“sulky, languid”), from past participle of Old English āseolcan (“be slow; be weak or slothful; languish”), from Proto-Germanic selkaną (“to fall in drops; dribble; droop”), from Proto-Indo-European sélǵ-o-nom, from selǵ- (“to let go, send”). Cognate with several Indo-Iranian words deriving from Proto-Indo-Iranian sarȷ́- (such as Sanskrit सृजति, सर्जन, सृक), possibly hit 𒊭𒀠𒀝𒍣 (“knead, mix”), although the semantic connection is weak.
Etymology from Wiktionary, CC BY-SA