Strong and resilient; sturdy.
The tent, made of tough canvas, held up to many abuses.
(of food) Difficult to cut or chew.
To soften a tough cut of meat, the recipe suggested simmering it for hours.
Rugged or physically hardy.
Only a tough species will survive in the desert.
Stubborn.
He had a reputation as a tough negotiator.
(of weather etc) Harsh or severe.
Rowdy or rough.
A bunch of the tough boys from the wrong side of the tracks threatened him.
(of questions, etc.) Difficult or demanding.
This is a tough crowd.
Undergoing plastic deformation before breaking.