be (as) tough as shoe leather
1. To be physically strong and/or rarely sick or injured; to be very tough. Marty has played in 500 straight games—he's tough as shoe leather. Bert is as tough as shoe leather, so get him to help you move all this furniture!
2. To have a tough, leathery skin (as of meat). This meat is as tough as shoe leather—I can't even cut it!