Entry 2 senses · 2 variants Webster, 1913 Sedative /sĕd'-ət-ĭv/ · Sed·a·tive · IPA /ˈsɛdətɪv/ a. n. 01 a. Tending to calm, moderate, or tranquilize 1. Tending to calm, moderate, or tranquilize(Med.) 02 n. A remedy which allays irritability and irritation, and irritative activity or pain. 1. A remedy which allays irritability and irritation, and irritative activity or pain.(Med.)