Preposterous/prɪˈpɑːstərəs/ Definition 1 of 1Pro Tip 1/3Exaggeration Used to describe something so extreme, it's hard to believe. Charging $100 for a cup of coffee is preposterous! Pro Tip 2/3Emotionally Charged Conveys strong feelings of disbelief or disapproval. Their preposterous behavior at the meeting shocked everyone. Pro Tip 3/3Not Always Humorous Can be serious criticism, not just something laughable. The politician's preposterous allegations could not be ignored.