"No way!", "Really?". "Usou" is actually the word for "a lie" but in informal speech is equilvalent to the American English "No way!" or "Really?" Usually used to indicate disbelief, e.g.: "No way!, that can't possibly be true!", sometimes used as a question, e.g.: "Really? Is that really true?" Since this is actually the word for lie, the word's usage is considered rude by many, particularly older people.