Insolent means showing rude disrespect toward someone who deserves courtesy or respect, especially someone in authority like a parent, teacher, or elder. When a student gives an insolent reply to a teacher's question, they're deliberately showing contempt or mockery through their words.

The word carries a sharp edge. It's not about forgetting to say “please” or accidentally interrupting someone. Insolent behavior is purposefully disrespectful. An insolent tone of voice drips with sarcasm or contempt. An insolent look might involve rolling your eyes or smirking when someone in authority is speaking to you seriously.

The related noun is insolence. A principal might warn a student about their insolence after they talk back rudely in class. In historical settings, showing insolence to nobility or military officers could lead to harsh punishment.

This isn't the same as respectfully disagreeing with someone or standing up for yourself when treated unfairly. Insolent behavior specifically means combining disrespect with arrogance: treating someone as if they're beneath you when they actually deserve your courtesy. The word helps us name a particular kind of rudeness that goes beyond ordinary impoliteness into deliberate contempt.