1 difficult to do or understand -- difícil
2 needing or using a lot of physical or mental effort -- duro, intenso
It was hard work on the farm, but satisfying.
3 not gentle or kind -- duro, intenso
He gave me a hard stare.
4 to criticize someone too much, or to treat them unfairly -- ser duro con alguien
5 to do or learn something by having a lot of problems or difficulty -- coger el camino difícil para hacer algo/aprender algo por las malas