break someone of something
Cause to discontinue a habit or practice, as in Mom tried for years to break Betty of biting her nails. The Oxford English Dictionary cites a quotation from W. Wotton's History of Rome (1701): "He ... broke them of their warm Baths," which presumably refers to breaking Romans of their custom of bathing regularly. Today we are more apt to break someone of a bad habit. [Early 1600s]