preventer
/prɪˈventə(r)/noun
1- a person or thing that prevents something防止者, 预防者; 妨碍物：
effective as preventers of further infection.
作为进一步感染的防止药物是有效的。
1.1
- Sailing an extra line or wire rigged to support a piece of rigging under strain, or to hold the boom and prevent it from gybing【航海】辅助索, 保险索。