psycho
noun /ˈsaɪkəʊ/
  /ˈsaɪkəʊ/
 (plural psychos)
 (informal)- a person who is mentally ill and who behaves in a very strange violent way
精神病患者;精神病人 - In his new film, he plays the part of a crazed psycho.
在他的新电影中,他扮演一个疯狂的神经病。  - Don’t let him drive—he’s a complete psycho behind the wheel!
别让他开车——他是个彻头彻尾的神经病!  
词源1930s: abbreviation. - In his new film, he plays the part of a crazed psycho.