haughty
Acting proudly rude, like you are better than others.
Haughty means acting like you think you're better than everyone else. A haughty person looks down on others with an air of superiority, as if regular rules and courtesies don't apply to them.
Imagine a student who rolls their eyes when classmates ask questions, sighs dramatically when working in groups, and speaks to others like they're bothering someone incredibly important. That's haughty behavior. Or picture someone who refuses to sit with certain kids at lunch because they consider themselves too good for that table. The word captures that nose-in-the-air attitude where someone treats ordinary kindness as beneath them.
You might encounter this word in older books describing proud aristocrats or villains who sneer at heroes.
What makes haughtiness particularly off-putting is the meanness baked into it. Confidence means believing in yourself; haughtiness means thinking that makes you superior to others. A talented musician can feel proud of their skills without being haughty about it. But when that same musician starts treating other players like they're wasting everyone's time, they've crossed into haughtiness.