The phrase "being the back of" implies being at or near the rear of something. Its antonyms would be "being the front of" or "being in front of," meaning being at or near the front of something. Other opposite phrases could include "being the center of," indicating being in the middle of something or "being on top of," implying being above or atop something. These antonyms represent different positions in space and can be used in different contexts depending on the situation. Understanding the opposite of a phrase can help to clarify its meaning and provide a more complete picture of the subject.