To condescend means to act like you're superior to someone else, treating them as if they're less intelligent or important than you. When someone condescends to you, they might use a sweet, patient voice while explaining something you already understand perfectly well, or they might give you a pat on the head when you've just accomplished something difficult.

The person is talking down to you, as if they're high up on a ladder looking down at someone below. A teacher condescends when they assume a capable student can't handle challenging work. An older sibling condescends when they explain simple things as if their younger brother or sister couldn't possibly figure them out alone.

You might hear someone described as condescending after they've treated others this way. A condescending remark might sound polite on the surface but carries an insulting undertone that suggests, “I'm smarter than you.” For example, saying “That's a good try for someone like you” is condescending because it implies the person couldn't be expected to do better.

The opposite of condescending is treating people with genuine respect, assuming they're capable and intelligent regardless of their age, experience, or background.