tough as an old boot
*tough as an old bootand *tough as old (shoe) leather
1. [of meat] very tough. (*Also: as ~.) This meat is tough as an old boot. Bob couldn't eat the steak. It was as tough as an old boot.
2. [of someone] very strong willed. (*Also: as ~.) When Brian was lost in the mountains, his friends did not fear for him; they knew he was tough as leather. My English teacher was as tough as an old boot.
3. [of someone] not easily moved by feelings such as pity. (*Also: as ~.) She doesn't care. She's as tough as old shoe leather. He was born tough as an old boot and has only grown more rigid.