What is the meaning of brooding?

noun

• Sitting on eggs so as to hatch them by the warmth of the body.
  • synonyms: incubation
• Persistent morbid meditation on a problem.
  • synonyms: pensiveness

verb

• Think moodily or anxiously about something.
  • synonyms: brood, dwell
• Hang over, as of something threatening, dark, or menacing.
  • usage: "The terrible vision brooded over her all day long"
  • synonyms: brood, hover, loom, bulk large
• Be in a huff and display one's displeasure.
  • usage: "She is pouting because she didn't get what she wanted"
  • synonyms: sulk, pout, brood
• Be in a huff; be silent or sullen.
  • synonyms: grizzle, brood, stew
• Sit on (eggs. )
  • usage: "Birds brood"; "The female covers the eggs"
  • synonyms: brood, hatch, cover, incubate

adjective

• Deeply or seriously thoughtful.
  • usage: "Byron lives on not only in his poetry, but also in his creation of the 'Byronic hero' - the persona of a brooding melancholy young man";
  • synonyms: broody, contemplative, meditative, musing, pensive, pondering, reflective, ruminative