pensiveness

from WordNet (r) 3.0 (2006)

pensiveness
    n 1: persistent morbid meditation on a problem [syn:
         {pensiveness}, {brooding}]
    2: deep serious thoughtfulness [syn: {pensiveness},
       {meditativeness}, {contemplativeness}]

from The Collaborative International Dictionary of English v.0.48

Pensiveness \Pen"sive*ness\, n.
   The state of being pensive; serious thoughtfulness;
   seriousness. --Hooker.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

33 Moby Thesaurus words for "pensiveness":
      absorption, abstraction, brown study, castle-building, close study,
      concentration, contemplativeness, daydreaming, deep thought,
      dreamery, dreamfulness, dreaminess, dreaming, dreamlikeness,
      engrossment, fantasying, gentle melancholy, melancholia,
      melancholiness, melancholy, musefulness, musing, pipe-dreaming,
      preoccupation, profound thought, reflectiveness, reverie,
      romantic melancholy, speculativeness, study, thoughtfulness,
      tristfulness, wistfulness