Hyperbole and metaphor are literary devices in which figurative language is used to express an idea rather than a literal statement or description. The term metaphor encompasses a range of these devices, with hyperbole being the specific subset related to exaggeration of the actual. Both poets and prose writers often employ hyperbole and metaphor to enhance artistry, reinforce the theme of their works, and elicit emotional responses.
The language of hyperbole and metaphor frequently comes in the form of images, or visual guides that can help a reader grasp an intangible characteristic. In William Shakespeare's tragedy Macbeth, for instance, the title character speaks of "sleep that knits up the ravel'd sleave of care." The first metaphor in this phrase involves sleep, which in scientific terms is a rest period activated by hormones but in Shakespeare's language is a knitter. The second metaphor involves "care," or worry — a mental state that is described as a frayed garment.
Shakespeare's metaphor succinctly describes how sleeping purges the mind's troubles and does so using literary techniques considered to have aesthetic value in their own right, such as alliteration and iambic pentameter. The play contains many other metaphors involving imperfect clothing, and they strengthen a thematic point of the work. Macbeth uses murder as his way to ascend the Scottish royal ranks until he is king, and scholars often interpret the images of clothes that are tattered or too loose on Macbeth as Shakespeare's metaphorical message about how ill the various titles Macbeth holds fit him.
The repetition surrounding Macbeth's attire illustrates the literary term conceit, which is an extended literary metaphor. Another common kind of metaphor is simile, a comparison of two things using the word "as," "like" or "than." A metonymy, meanwhile, refers to an object not by its proper name but by something familiarly associated with it. For instance, the use of a chariot to represent the inevitable passage of time toward death dates to Greek mythology. It surfaces in Metaphysical poet Andrew Marvell's "To His Coy Mistress" — "winged chariot hurrying near" — as well as American poet Emily Dickinson's "Because I Could Not Stop for Death," which includes the line "A carriage carries the speaker, Death and Immortality."
Hyperbole is also a particular type of metaphor — one that relies on overstatement. The writer who uses hyperbole distorts not only the nature of a situation but also its scale. His purpose may be to express strong emotions or rouse sympathies for himself.
American playwright Tennessee Williams' A Streetcar Named Desire includes hyperbole and metaphor throughout. Stanley Kowalski, the main male character, complains about how his wife and sister-in-law have been comparing him to animals, such as a pig and an ape. In response to their metaphors, he asks, "What do you think you are, a pair of queens?" Stanley probably correctly assesses that the women think they are his betters while knowing they do not literally consider themselves royalty. He likely engages in hyperbole in an outburst of anger and to put on a show of force to try to quell his relatives' condescension.