Synonyms and related words :
absence of mind, absentmindedness, absorption, abstractedness, abstraction, bemusement, brown study, castle-building, daydream, daydreamer, daydreaming, depth of thought, dream, dreaming, engrossment, fantasy, fantasying, fit of abstraction, mooning, moonraking, muse, musefulness, musing, muted ecstasy, pipe dream, pipe-dreaming, preoccupation, reverie, stargazing, study, trance, woolgathering