› [I or T] COMMERCE, MARKETING to stop buying the products or services of a particular company, especially in order to buy them from a competitor › [I or T] HR to frequently replace employees with new employees › [T] STOCK MARKET if stockbrokers churn investments or churn a client's account in order to make more money in commissions, they illegally buy and sell the client's investments more often than necessary: The commission found that he violated the antifraud provisions of the securities laws when he churned three customer accounts.