Dis- is a prefix that attaches to the beginning of words to reverse their meaning or show the opposite of something. When you disagree with someone, you take the opposite position. When you dislike a food, you have a negative feeling toward it. When you disappear, you go out of sight.

Think of dis- as a verbal eraser. It takes the base word and flips it around. If you assemble a puzzle, you put it together; if you disassemble it, you take it apart. If you connect two things, you join them; if you disconnect them, you separate them. A respectful student shows respect; a disrespectful one acts without it.

Sometimes dis- suggests removal or reversal of an action beyond simple negation. When you disarm someone, you take away their weapons. When you disband a club, you break it up. When you're dishonest, you actively move away from honesty rather than merely lacking it.

You'll find dis- everywhere in English because it's such a useful tool for expressing opposites and for undoing actions.