Synonyms to be absent

daydream, Walter Mitty, absence of mind, absentmindedness, absorption, abstractedness, abstraction, airy nothing, autism, bad dream, bemusement, brown study, bubble, castle-building, chimera, conceiving, daydreamer, daydreaming, deception, deluded belief, delusion, depth of thought, dereism, divagate, dream, dream of, dream vision, dreaming, dreamland, dreamworld, engrossment, false belief, fantasy, fantasying, fit of abstraction, freak out, go woolgathering, ignis fatuus, illusion, imagination, imagining, incubus, misbelief, misconception, moon, mooning, moonraking, muse, musefulness, musing, muted ecstasy, nightmare, nostalgia, phantasm, pipe dream, pipe-dream, pipe-dreaming, preoccupation, reverie, self-deceit, self-deception, self-delusion, stargaze, stargazing, stray, study, trance, trick, trip, vapor, vision, wander, wishful thinking, wishfulness, wistful eye, wistfulness, woolgathering, wrong impression, yearnfulness, default, AWOL, French leave, abscondence, absence, absence without leave, absentation, absenteeism, absenting, arrear, arrearage, arrears, back debts, back payments, ba