tough cookie
You're tough as nails.
I'm a tough guy.
I'm tough as nails.
Malgré son apparence de dur à cuire, Yanni est quelqu'un de très sympathique.
Despite his tough-guy appearance, Yanni is a very friendly person.
Sami avait une allure de dur à cuire.
Sami had a tough guy look.
He's a tough guy.