Antonyms for the phrase "be equivalent to" include "be inferior to," "be dissimilar to," and "be unequal to." When something is inferior to another, it is of a lower quality or standard. If two things are dissimilar or different, they cannot be equivalent to each other. And when something is unequal to another, it means there is a significant difference in terms of value or worth. These antonyms highlight the idea that not everything is equivalent or equal, and the importance of recognizing and acknowledging differences. Understanding antonyms can help expand one's vocabulary and provide a better understanding of language.