Dumbfounded/dʌmˈfaʊndɪd/ Definition 1 of 1Pro Tip 1/3Surprise Intensity Use 'dumbfounded' to express a high level of surprise, more than just 'surprised' or 'shocked'. She was dumbfounded when she won the lottery. Pro Tip 2/3Speechlessness 'Dumbfounded' often implies being so amazed that one is temporarily unable to speak. The magician left the audience dumbfounded with his act. Pro Tip 3/3Negative or Positive Can be used for positive surprises like winning an award or negative ones like an unexpected breakup. He was dumbfounded by the unexpected breakup.