Antagonize means to deliberately provoke someone or make them angry. When you antagonize your sister by hiding her favorite book right before she needs it for school, you're purposely doing something you know will upset her. When a student keeps interrupting the teacher with silly questions just to be annoying, they're antagonizing the teacher.

The word carries a sense of intentional provocation. You're knowingly pushing someone's buttons and trying to get a reaction from them. A younger brother might antagonize his older sibling by repeating everything they say, or by poking them while they're trying to concentrate. In stories, villains often antagonize heroes by taunting them or threatening what they care about most.

Sometimes people antagonize others without realizing the consequences. You might antagonize a normally friendly dog by pulling its tail, turning a calm situation tense or even dangerous. In conflicts between countries or groups, leaders try to avoid antagonizing each other because provocations can escalate into serious problems.

The related word antagonist means an opponent or enemy, especially the main villain in a story who works against the hero. Whether it's Shere Khan in The Jungle Book or the White Witch in The Lion, the Witch and the Wardrobe, an antagonist is someone whose goals conflict with the protagonist's goals.