Antonyms are words that have opposite meanings to each other. In the case of the term "cerebral primitive neuroectodermal tumor," which refers to a type of brain tumor, antonyms might include words like healthy, normal, and noncancerous. These terms represent the opposite of a tumor or abnormal growth in the brain. Other possible antonyms might include words like stable, steady, and unchanging, as these words describe a condition that is not characterized by rapid, unpredictable growth or change. While antonyms may seem like a simple concept, they can help us understand complex medical terms and conditions by providing a frame of reference for comparison.