difficult, hard
E pode ter certeza, eles serão difíceis de bater.
And you can be sure, they will be hard to beat.
— Lagaan: A Coragem de um Povo (2001)
Os princípios básicos da gramática não são tão difíceis.
The basic principles of grammar aren't that difficult.
Todas as perguntas eram difíceis de responder.
All the questions were difficult to answer.
As frases do Tom são realmente difíceis de traduzir.
Tom's sentences are really difficult to translate.
We are difficult people.