Sweetheart deal is a term used to describe an agreement or transaction that is beneficial to one party and generally unfair to others. There are several synonyms for this term, including "backroom deal," "under the table agreement," and "favorable arrangement." Other synonyms could include "collusion," "insider trading," and "cronyism." These terms are often associated with corruption and unethical practices. It is important to be cautious when engaging in any business deal or transaction, and to ensure that all parties involved are treated fairly and equally. The use of these synonyms highlights the importance of maintaining transparency and honesty in all business practices.