v (transitive) To agitate rapidly and repetitively, or to stir with a rowing or rocking motion; generally applies to liquids, notably cream.
v (transitive, figuratively) To produce excessive and sometimes undesirable or unproductive activity or motion.
v (intransitive) To move rapidly and repetitively with a rocking motion; to tumble, mix or shake.
v (of a customer) To stop using a company's product or service.
v (informal, travel, aviation) To repeatedly cancel and rebook a reservation in order to refresh ticket time limits or other fare rule restrictions.
v (US, informal, finance, travel) To continually sign up for new credit cards in order to earn signup bonuses, airline miles, and other benefits.
v (finance) To carry out wash sales in order to make the market appear more active than it really is.
n A vessel used for churning, especially for producing butter.
n A milk churn (container for the transportation of milk).
n Customer attrition; the phenomenon or rate of customers leaving a company.
n (telecommunications) The time when a consumer switches his/her service provider.
n (telecommunications) The mass of people who are ready to switch carriers.
n Cyclic activity that achieves nothing.
n (historical) The last grain cut at harvest; kern.