An idiom is a phrase with a meaning that is different from the literal meaning of the words. Idioms exist in every language and culture, though their origins are unknown. Learning idioms can be confusing for non-native speakers, as the meanings are not obvious. Idioms add interest and imagery to writing by vividly describing situations, attitudes, and behaviors in a unique way. They are commonly used in casual conversation and classic literature to creatively convey intended meanings.