Sweetheart deal
A sweetheart deal or sweetheart contract is an abnormally favorable contractual arrangement. A particularly lucrative golden parachute could be an example of a type of sweetheart deal, where it is not in the best interests of the stockholders. It particularly applies to government officials and uses of the term involve hints at the presence of corruption. Such deals may also put a third party at a distinct disadvantage, (e.g. price fixing between oil companies or mobility services).
In the context of employment rights, a sweetheart contract can involve a deal between an employer and trade union officials that benefits both at the expense of employees.