Entry 1 sense Webster, 1913 masturbation /măsˌ-tẽrb-āsh'-ən/ · mas·tur·ba·tion · IPA /ˌmæstɚˈbeɪʃən/ 01 n. The act of masturbating; sexual self-gratification; onanism. 1. The act of masturbating; sexual self-gratification; onanism.