The word "most fuddy-duddy" may refer to someone who is old-fashioned, rigid, and unfashionable. Its antonyms would be modern, trendy, and fashionable. Other possible antonyms could include flexible, open-minded, and innovative. Someone who is modern would be up-to-date with the latest trends and styles, while someone who is trendy would be fashionable and stylish. Being flexible means being adaptable to change and willing to try new things. Open-minded people are receptive to new ideas and perspectives, while innovative people are creative and resourceful. All of these antonyms describe individuals who are the opposite of a fuddy-duddy, and who embrace new and exciting experiences.