The antonyms for "un-fulfilling" are "fulfilling," "gratifying," "satisfying," and "rewarding." These words describe experiences or situations that provide a sense of accomplishment, happiness, and contentment. Fulfilling activities could be achieving a goal, helping someone in need, or pursuing a passion. Gratifying experiences could be receiving recognition for hard work or achieving something important. Satisfying experiences could be completing a challenging task or solving a complex problem. Rewarding experiences could be getting a promotion, discovering something new, or receiving praise for a job well done. These antonyms describe experiences that bring purpose, satisfaction, and fulfillment to life.