Stubborn or persistent; capable of stubbornness or persistence.
Harsh or severe.
Difficult or demanding.
Strong and resilient; sturdy.
Undergoing plastic deformation before breaking.
Difficult to cut or chew.
Rugged or physically hardy.
Rowdy or rough.
Used to indicate lack of sympathy
A person who obtains things by force; a thug or bully.
To endure.
To toughen.
Not worthy; lacking value or merit; worthless.
An inadequate person.