an evil and cruel person

He was portrayed in the media as a complete fiend. 他被媒体描绘成了一个十足的恶魔。

someone who likes something very much or is very interested in something

a health/sex/chocolate fiend 健身爱好者／色魔／疯狂喜爱巧克力的人

McCormack is a fiend for punctuality. 麦科马克极其守时。