Synonyms for Castles in the air:

• adj.

  •fanciful (adjective)
  • fabulous,
  • bizarre,
  • legendary,
  • illusory,
  • poetic,
  • fantastic,
  • extravagant,
  • chimerical,
  • fictitious,
  • capricious,
  • fancied,
  • imagined,
  • absurd,
  • pipe dream,
  • mythical,
  • aerial,
  • fantastical,
  • on cloud nine,
  • offbeat,
  • kinky,
  • whimsical,
  • suppositious,
  • shadowy,
  • visionary,
  • fictive,
  • imaginative,
  • wild,
  • curious,
  • preposterous,
  • pie in the sky,
  • dreamlike,
  • ideal,
  • floating,
  • unreal,
  • flaky.

• n.

  •daydream (noun)
  • daydream.
  •reverie (noun)
  • absentmindedness,
  • absorption,
  • dreamings,
  • woolgathering,
  • fool's paradise,
  • detachment,
  • dreaming,
  • musing,
  • muse,
  • trip,
  • study,
  • abstraction,
  • pensiveness,
  • thought,
  • contemplation,
  • fantasy,
  • castle-building,
  • preoccupation,
  • phantasy,
  • head trip,
  • meditation,
  • inattention,
  • dreaminess,
  • absent-mindedness,
  • mind trip,
  • phantasies,
  • trance.

• Other synonyms:

  •
  • fairyland.

Antonyms for Castles in the air:

• adj.

  • fanciful
    unfanciful, ordinary, grave, normal, unimaginative, sensible, unromantic, usual, real, serious, sincere, reasonable.

• n.

  • reverie
    nightmare.
  • vision
    blindness, actuality, existence, fact, sightlessness, substance, truth, being, ignorance, reality.