condescending

Showing that you think you are better or know more than the person you are speaking to.

It describes a superior attitude that can come through in someone's words, tone, or behavior, even when they seem polite. It is strongly disapproving.

• I know you mean well, but that sounded condescending.
• She explained the new system without being condescending.
• His condescending tone made me feel like he thought I couldn't understand.