pensiveness

noun

1. (uncountable)A thoughtful or reflective state, especially if sad or melancholic.

   “We left quietly so as not to disturb the widow's pensiveness.”

   “Yet the employment seemed a pleasant one; her cheek was flushed with a clear, rich crimson—her face / "Was like any fair lake that the morning is on, / When it breaks into dimples, and laughs in the sun." / And if, ever and anon, the brow was clouded by a shade of pensiveness, it was quickly dispelled by the consciousness of present happiness.”