Entry 1 sense Webster, 1913 Tranquilizing /trăng'-kwəl-īzˌ-ĭng/ · Tran·quil·i·zing · IPA /ˈtɹæŋkwɪˌlaɪzɪŋ/ 01 a. Making tranquil; calming. 1. Making tranquil; calming.