disaccustom (v.)

late 15c., "render a thing no longer customary" (a sense now obsolete); 1520s in modern sense "render (a person) unaccustomed to (something), cause to lose (a habit) by disuse," from Old French desacostumer "render unfamiliar" (Modern French désaccoutumer), from des- "not, opposite of" (see dis-) + acostumer "become accustomed, bring into use" (see accustom). Discustom (c. 1500) also was used. Related: Disaccustomed.