Answer:
Figurative language, also called a figure of speech, is a word or phrase that departs from literal language to express comparison, add emphasis or clarity, or make the writing more interesting with the addition of color or freshness.
Metaphors and similes are the two most commonly used figures of speech, but hyperbole, synecdoche, and personification are also figures of speech that are in a good writer's toolbox.
A metaphor compares two things by suggesting that one thing is another: "The United States is a melting pot."
A simile compares two things by saying that one thing is like another: "My love is like a red, red rose."
Hyperbole is a form of exaggeration: "I would die without you."
Synecdoche is a literary device that uses the part to refer to the whole: "The crown has declared war" rather than "The king (or the government) has declared war."
Personification involves giving non-living things the attributes of a living thing: "The car is feeling cranky today."
Figurative language enhances your fiction if it's used competently and can be an economical way of getting an image or a point across. But if it's used incorrectly, figurative language can be confusing or downright silly -- a true mark of an amateur writer. Figurative language can also be described as rhetorical figures or metaphorical language; whichever term you use, these are called literary devices.