|Origin:||Probably from an unrecorded Anglo-French solein 'single, solitary, sullen', from Latin solus 'alone'|
angry and silent, especially because you feel life has been unfair to you:
Bill sat in sullen silence and refused to eat his lunch.
a look of sullen resentment
a sullen sky or sea is dark and looks as if bad weather is coming
—sullenness noun [uncountable]