A single word that can be offensive to someone is a horrible thing for anyone who has iman. In other words, filthy language out of your mouth and faith inside your heart cannot coexist. You cannot have iman in your heart and ugly words come out of your mouth. If you have no control over whatever four letter words you keep using every time you get frustrated, there's a spiritual problem, it's not just a habit problem. How can you use a terrible word for anyone who has iman?