A person who obtains things by force; a thug or bully.

To endure.

To toughen.

(of a material) Strong and resilient; sturdy.

(of food) Difficult to cut or chew.

(of a person or animal) Rugged or physically hardy.

(of a person) Stubborn or persistent; capable of stubbornness or persistence.

(of weather, etc.) Harsh or severe.

Rowdy or rough.

(of questions, etc.) Difficult or demanding.

(material science) Undergoing plastic deformation before breaking.

Strict, not lenient.

(slang) Used to indicate lack of sympathy