The phrase "is on top heap" implies a sense of superiority or dominance, but in the world of antonyms, there are many words that can convey the opposite sentiment. Words like "bottom," "underdog," "inferior," and "last" all represent positions that are opposite to being on top. Other antonyms for this phrase might include words like "losing," "inferior," "defeated," "lagging," or "trailing." Essentially, any word that suggests a lower status, less power, or inferior position could serve as an antonym for "is on top heap." Whether you're talking about sports teams, business leaders, or personal relationships, the concept of being on top is relative, and there are always antonyms to be found.