THESAURUS
castle building
Walter Mitty, absence of mind, absentmindedness, absorption, abstractedness, abstraction, bemusement, brown study, daydream, daydreamer, daydreaming, depth of thought, dream, dreamery, dreamfulness, dreaminess, dreaming, dreamlikeness, engrossment, fantasy, fantasying, fit of abstraction, mooning, moonraking, muse, musefulness, musing, muted ecstasy, pensiveness, pipe dream, pipe-dreaming, preoccupation, reverie, stargazing, study, trance, woolgathering