pfft

interjection
  1. used to represent a short, sharp sound of dismissal, skepticism, or contempt
  2. Usage: informal; often used to express doubt or disbelief
  3. used to represent a soft, quick sound like air escaping or a small explosion
  4. Usage: informal; onomatopoeia
noun
  1. a short, sharp sound of dismissal or contempt
  2. Usage: informal

Examples