killer
noun
1 (person) 杀手; (illness, poison, etc.) 致命之物;
cancer is a major killer 癌症是一大致命杀手;
killer virus/bees 致命病毒/杀人蜂;
sharks can be vicious killers 鲨鱼有时会变成残忍的杀手
2 informal (sth difficult) 棘手的事;
this hill is a killer! 这座山可难爬了!;
the exam was a real killer! 这考试真让人头疼!
3 informal (sth funny) 十分有趣的事;
that joke's a killer! 那个笑话真逗!