Sardonicism is a term that refers to a type of humor or wit that is often mocking or cynical. Its antonyms, on the other hand, would be more upbeat and cheerful, with a positive or lighthearted tone. Some possible antonyms for sardonicism include sincerity, earnestness, optimism, and genuine enthusiasm. These words imply a sense of honesty, integrity, and authenticity that is often lacking in the sarcastic or ironic tone of sardonic humor. Other antonyms might include amiability, geniality, goodwill, and kindness, all of which suggest a warmth of spirit and a willingness to connect with others in a positive way.