"Sell soul" is a phrase commonly used to describe the act of sacrificing one's integrity or moral principles in exchange for personal gain, especially financial gain. Some synonyms for this phrase include "betray one's values," "compromise one's ethics," "trade one's conscience," or "give up one's moral compass." Other related phrases include "sell out," "be bought off," and "do whatever it takes." These expressions all convey the idea of sacrificing one's personal beliefs and values in order to achieve a desired outcome, often at the expense of others or at the cost of one's own moral well-being.