IPA: /ˈsʌlənəs/
KK: /ˈsʌlənəs/
The state of being gloomy or silent because of being unhappy or angry.
His sullenness made it difficult for others to approach him.
**Sullenness** → It is formed from "sullen" (from Old French *solen*, meaning gloomy or morose) and the suffix "-ness" (meaning the state or quality of). The word "sullenness" refers to the state of being gloomy or morose.
Think of the word 'sullen' which describes a gloomy mood, and remember that 'sullenness' means the quality of being in that gloomy state.