conceit

noun
  1. An excessively favorable opinion of one's own ability, importance, wit, etc.; vanity. noun
    His conceit about his own intelligence was evident to everyone.
    She was full of conceit, always boasting about her achievements.
  2. An elaborate or strained metaphor, often found in poetry. noun
    The poem was full of conceits that compared love to a voyage.
    Metaphysical poets are known for their use of conceits in their work.
  3. A fanciful idea or notion. noun
    The architect's design was based on a conceit of futuristic living.
    The novel's plot was built around a clever conceit.
  4. A thought or opinion, especially an imaginative one. noun
    The conceit that humans could colonize Mars is both exciting and daunting.
    His conceit about the future of technology was intriguing.