conceit
n.n. a belief that you are much more important or clever than other people. It can also mean a clever or original idea that shows off the writer's skill.
n. an exaggerated sense of self-importance or intellectual superiority. In a literary context, it refers to a clever or elaborate metaphor or figure of speech that displays the author's ingenuity.
His arrogance was nothing more than a simple conceit.
The poet's use of a grand conceit comparing the heart to a clock demonstrates his mastery of metaphor.
While the protagonist's conceit makes him a difficult character to like, it also serves as a vehicle for the author's exploration of human hubris.
From Middle English conceyte, formed from conceyven by analogy with pairs such as (Modern English) deceive~deceit, receive~receipt etc. Doublet of concept and concetto. Akin to Portuguese conceito.