The concept of "pain pleasure principle" revolves around the idea that humans as well as animals tend to seek pleasure and avoid pain. However, just like any other word or phrase, "pain pleasure principle" also has antonyms or opposite meanings. One such antonym for pain would be pleasure, meaning the opposite feeling of pain or discomfort. Additionally, the opposite of pleasure would be pain, meaning a sense of unease or discomfort. Moreover, words like sorrow, grief, and distress also denote the opposite of pleasure. On the other hand, contentment, delight, and joy are some of the antonyms for pain in relation to the pleasure principle.