be (as) tough as old boots

1. To be very physically strong and resilient. Marty has played in 500 straight games without so much as a sprained ankle—he's as tough as old boots. My grandfather did a lot of physical labor around the family farm, so he was tough as old boots. A: "Can you believe Aunt Anita is still rowing at 87?" B: "I know, she's tough as old boots."

2. To have a tough, leathery texture. Said especially of meat. This meat is as tough as old boots—I can't even cut it! No, the steak won't be tough as old boots this time, I cooked it completely differently. How does she manage to dry out the turkey every year? Once again, it's as tough as old boots!

3. To not feel or show one's emotions; to be very stoic. Our aunt is as tough as old boots, so we asked her to give the eulogy, knowing that she's the only one who could do it without crying. We need someone who is tough as old boots at the head of the company when times get rough. The tragedy has been really hard on our whole family, but my wife has been as tough as old boots throughout it all.

4. To be extremely stubborn or determined. You'll never get Rich to change his opinion—he's as tough as old boots. My dad can be as tough as old boots when he makes up his mind about something, even when we can prove that he's wrong. We've got a new boss in the office who's tough as old boots and thinks her way of doing things is the only correct one.