silencer
noun [ C ] uk/ˈsaɪ.lən.sər/ us/ˈsaɪ.lən.sɚ/
（枪支的）消音器
a piece of equipment that you use on a gun to reduce the noise made when it fires
UK (US and Australian English muffler)（发动机上的）消音器
a part of a vehicle that reduces noise from the engine