Antithesis means the direct opposite of something, or the sharpest possible contrast between two things. If someone calls you the antithesis of lazy, they mean you're incredibly hardworking. If a library is the antithesis of a noisy playground, that emphasizes how quiet and calm it is compared to how loud and energetic the playground is.

In ancient Greek rhetoric, speakers would deliberately place contrasting ideas side by side to make both more powerful. When Charles Dickens began his novel A Tale of Two Cities with the line “It was the best of times, it was the worst of times,” he was using antithesis to set up a strong contrast between two ways of seeing the same period in history.

You'll often see antithesis used to make a point more dramatic. A teacher might say that a messy, disorganized essay is the antithesis of what she's looking for. A coach might call quitting the antithesis of the team's never-give-up spirit. The word suggests not just difference, but the strongest, clearest possible opposition between two ideas or things. When you say something is the antithesis of something else, you're drawing a clear line between them.