tranquillizer
noun [ C ] UK (UK also tranquilliser); (US tranquilizer) uk/ˈtræŋ.kwɪ.laɪ.zər/ us/ˈtræŋ.kwə.laɪ.zɚ/
安定药;镇静剂
a drug used to make a person or animal calmer
She was on tranquillizers for a long time after her son died. 儿子死后，她很长一段时间一直服用镇静剂。