insulator
noun [ C ] uk/ˈɪn.sjə.leɪ.tər/ us/ˈɪn.sə.leɪ.t̬ɚ/
绝缘体；（隔热或隔音）物
a material or covering that electricity, heat, or sound cannot go through
Generally, plastics tend to be good insulators. 一般说来，塑料往往是很好的绝缘体。
Compare: conductor