Churning refers to the unethical and excessive trading of securities in a customer's account for the sole purpose of earning commissions or profits, without taking into account their investment objectives. This deceptive practice is considered illegal and can have detrimental effects on an individual's financial well-being. It is important for investors to be aware of churning and its consequences, and to work with reputable and trustworthy financial advisors who prioritize their clients' best interests.