Impertinence is rude behavior that shows a lack of proper respect, especially toward someone who deserves courtesy or deference. When a student responds to a teacher's question with sarcasm or mockery, that's impertinence. When someone interrupts an adult who's speaking or talks back in a disrespectful way, they're being impertinent.

The word carries a specific shade of meaning: it suggests someone is overstepping boundaries or acting above their station. An impertinent remark is deliberately cheeky or presumptuous. If you asked your teacher, “Why should I care what you think?” that would be impertinent because it challenges their authority in a disrespectful way.

Impertinence is different from honest disagreement or asking genuine questions. You can respectfully disagree with someone or question their reasoning without being impertinent. The key difference is in the tone and intent: impertinence shows contempt or dismissiveness rather than thoughtful disagreement.

An impertinent person acts as if normal rules of courtesy don't apply to them, as if respect were somehow irrelevant to their situation.