Synonyms and related words :
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