If something is indisputable, it is so clearly true that you have to accept it — you cannot honestly argue it away. People use it about facts, proof, and results you can point to: an indisputable fact, indisputable evidence. It is a formal, slightly heavy word. In everyday talk, people more often say “you can’t argue with that” or just “that’s true.” Though actually, calling something indisputable is sometimes a way of shutting a door on debate, not a lab result; the speaker wants the argument to stop. You will also hear it about people and titles — an indisputable champion — meaning the win is not in doubt. A close everyday cousin is undisputed, which is a little more common in speech.