spam filter
noun [ C ] uk/ˈspæm ˌfɪl.tər/ us/ˈspæm ˌfɪl.t̬ɚ/
垃圾邮件过滤器,垃圾邮件过滤机制
a piece of software that prevents spam (= unwanted email, usually advertisements) from reaching your inbox (= the place on a computer where emails that are sent to you are kept)