In Spanish, the word for ‘hard’ is ‘duro’ when referring to something physically hard or tough. For example, you might say ‘La piedra es dura’ which means ‘The stone is hard.’
If you are referring to something that is difficult, the word ‘difícil’ is used. For instance, ‘El examen fue difícil’ translates to ‘The exam was hard.’
Both words are commonly used in everyday conversations, so it’s important to know the context in which to use them.