A metaphor is a figure of speech that makes a direct comparison between two unrelated things, suggesting that one thing is another. This comparison helps to create vivid imagery and convey deeper meanings without using "like" or "as." For example, saying "time is a thief" implies that time steals moments from our lives, even though time is not literally a thief. Metaphors are commonly used in literature, poetry, and everyday language to enhance expression and understanding. They can evoke emotions and paint pictures in the reader's mind, making complex ideas more relatable. For instance, in Shakespeare's works, metaphors enrich the text and provide insight into characters and themes.