A more thorough explanation:

A slush fund is money that is set aside for unspecified purposes, often for corrupt activities, and is not subject to financial procedures that ensure accountability. It is a secret stash of money that can be used for any purpose without any oversight or transparency.

• A politician may have a slush fund to bribe other politicians or to fund their election campaign without disclosing the source of the money.
• A company may have a slush fund to pay off officials or to engage in illegal activities.

These examples illustrate how a slush fund can be used for unethical or illegal purposes without any accountability. It is a way for individuals or organizations to operate outside the law and to avoid detection.