Antonyms are words that have opposite meanings to another word. In the case of coelenterate venom, which refers to the poisonous secretion of jellyfish, anemones, and other related species, some possible antonyms include harmless, safe, non-toxic, and benign. These terms describe substances or organisms that do not pose any danger or harm to living beings, unlike coelenterate venom that can cause severe allergic reactions, pain, and even death in some cases. Other related antonyms could be beneficial, helpful, or symbiotic, which refer to organisms that have a positive impact on their environment or interact in a mutually beneficial way with other species.