HAVE SOMETHING ON

{v. phr.}, {informal} To have information or proof that someone did something wrong. * /Mr. Jones didn't want to run for office because he knew the opponents had something on him./ * /Mr. Smith keeps paying blackmail to a man who has something on him./ * /Although Miss Brown is not a good worker, her boss does not fire her because she has something on him./ Compare: GET THE GOODS ON. Contrast: HAVE NOTHING ON.