[n] a drug used to reduce stress or tension without reducing mental clarity [adj] tending to soothe or tranquilize; "valium has a tranquilizing effect"; "took a hot drink with sedative properties before going to bed"
antianxiety agent, ataractic agent, ataractic drug, ataraxic, depressant, sedative, tranquilising, tranquilizer, tranquilizing, tranquilliser, tranquillizer