PFFT is an interjection used to express disbelief, derision, or dismissal. It is often used in response to something that is considered ridiculous or absurd. YEAH RIGHT is another interjection used to express disbelief or sarcasm. It is often used to indicate that someone does not believe what they have been told. PSHAW is an interjection used to express contempt, disbelief, or disapproval. It is often used in response to something that is considered foolish or ridiculous.