frightener
/ˈfraɪtənə(r)/noun
1- a person or thing that frightens someone使人害怕的人（或事）。
1.1
- Brit. informal a member of a criminal gang who intimidates its victims〈英, 非正式〉恐吓受害人的犯罪团伙成员。
短语
put the frighteners on
- Brit. informal threaten or intimidate (someone)〈英, 非正式〉威胁; 胁迫。