churn

(transitive) To agitate rapidly and repetitively, or to stir with a rowing or rocking motion; generally applies to liquids, notably cream.

(transitive, figuratively) To produce excessive and sometimes undesirable or unproductive activity or motion.

(intransitive) To move rapidly and repetitively with a rocking motion; to tumble, mix or shake.

(of a customer) To stop using a company's product or service.

(informal, travel, aviation) To repeatedly cancel and rebook a reservation in order to refresh ticket time limits or other fare rule restrictions.

(US, informal, finance, travel) To continually sign up for new credit cards in order to earn signup bonuses, airline miles, and other benefits.

(finance) To carry out wash sales in order to make the market appear more active than it really is.