An elaborate and complicated metaphor. An early exponent of conceits was the 14th Century Italian poet Petrarch. The Petrarchan conceit was imitated by many Elizabethan poets including Shakespeare. Conceits were also used extensively by the metaphysical poets. John Donne famously compared two lovers to a pair of compasses in his poem A Valediction: forbidding Mourning.
[n] the trait of being vain and conceited
[n] feelings of excessive pride