{n. phr.}, {informal} No good proof or excuse; no good evidence or defense to offer. * /The man with a gun and $300 in his pocket was accused of robbing an oil station. He did not have a leg to stand on./
NOT A LEG TO STAND ON
Meaning of NOT A LEG TO STAND ON in English
Dictionary of English idioms . Словарь английских идиом. 2012