In the modern literary criticism, more common with genre fiction, conceit often means an extended rhetorical device, summed up in a short phrase, that refers to a situation which either does not exist, or exists rarely, but is needed for the plot. "Faster than light travel" and "superior alien science" are examples from science fiction; the "hardboiled private gumshoe" is an example from detective stories. The word conceit was originally coined in the context of poetry, deriving from the root concept, conceive. It has subsequently been extended to other forms of literature, the performing arts, painting, photography, and even architecture.
Use as praise versus criticism
The term conceit can be used positively or derogatorily.
In the positive sense, a conceit originally referred to an extended metaphor with a complex logic that governs a poetic passage or entire poem. By juxtaposing images and ideas in surprising ways, a conceit invites or challenges the reader to discover a more sophisticated understanding of an object of comparison. Conceits in English are part of the poetic idiom of Mannerism, during the late sixteenth and early seventeenth century. This has been extended to describe presentation of any material whose creator uses one or more techniques to effectively induce a desired effect on the reader or viewer, such as setting a mood. In movie-making, examples include deliberately filming in black and white, emphasizing shadows, using panoramic views or employing extended zoom for a scene.
In a derogatory sense, "conceit" refers to an excessively elaborate, contrived or unconvincing approach to the material being presented, such as a fundamentally flawed idea, preposterous plot device, or pretentious dialog or phrasing. Again, this was originally applied to poetry that someone disliked, and the areas of application later broadened. An example of derogatory use is in the title of economist Friedrich Hayek's book, "The Fatal Conceit: The Errors of Socialism"
In modern writing, the word "conceit", when used by itself without preceding adjectives, tends to be used more often as criticism than as praise. Such use is especially common when writing for a broad audience rather than specialists in poetry or literary criticism. Which sense is actually intended, however, must be inferred from the overall content and tone of the passage containing the phrase.
In poetry
Metaphysical
In English literature the term is generally associated with the 17th centurymetaphysical poets, an extension of contemporary usage. The metaphysical conceit differs from an extended analogy in the sense that it does not have a clear-cut relationship between the things being compared. Helen Gardner observed that "a conceit is a comparison whose ingenuity is more striking than its justness" and that "a comparison becomes a conceit when we are made to concede likeness while being strongly conscious of unlikeness." An example of the latter occurs in John Donne's "A Valediction: Forbidding Mourning", in which a couple faced with absence from each other is likened to a compass. Dull sublunary lovers' love cannot admit Absence, because it doth remove Those things which elemented it. But we by a love so much refined, That our selves know not what it is, Inter-assured of the mind, Care less, eyes, lips, and hands to miss. Our two souls therefore, which are one, Though I must go, endure not yet A breach, but an expansion, Like gold to airy thinness beat. If they be two, they are two so As stiff twin compasses are two; Thy soul, the fixed foot, makes no show To move, but doth, if the other do. And though it in the center sit, Yet when the other far doth roam, It leans and hearkens after it, And grows erect, as that comes home. Such wilt thou be to me, who must, Like th' other foot, obliquely run; Thy firmness makes my circle just, And makes me end where I begun. The metaphysical conceit is often imaginative, exploring specific parts of an experience. John Donne's "" is a poem seemingly about fleas in a bed. When Sir Philip Sidney begins a sonnet with the conventional idiomatic expression "My true-love hath my heart and I have his", he takes the metaphor literally and teases out a number of literal possibilities in the exchange of hearts. The result is a fully formed conceit.
Petrarchan
The Petrarchan conceit is a form of love poetry wherein a man's love interest is referred to in hyperbole. For instance, the lover is a ship on a stormy sea, and his mistress is either "a cloud of dark disdain" or the sun. The paradoxical pain and pleasure of lovesickness is often described using oxymoron, for instance uniting peace and war, burning and freezing, and so forth. But images which were novel in the sonnets of Petrarch, in his innovative exploration of human feelings, became clichés in the poetry of later imitators. Romeo uses hackneyed Petrarchan conceits when describing his love for Rosaline as "bright smoke, cold fire, sick health".
Etymology
In the Renaissance, the term indicated any particularly fanciful expression of wit, and was later used pejoratively of outlandish poetic metaphors. Recent literary critics have used the term to mean simply the style of extended and heightened metaphor common in the Renaissance and particularly in the 17th century, without any particular indication of value. Within this critical sense, the Princeton Encyclopedia makes a distinction between two kinds of conceits: the Metaphysical conceit, described above, and the Petrarchan conceit. In the latter, human experiences are described in terms of an outsized metaphor, like the stock comparison of eyes to the sun, which Shakespearemakes light of in his Sonnet 130: "My mistress' eyes are nothing like the sun."