public enemy number one 头号公敌，危害最大的人或事情

【例句】
She was being made to feel like public enemy number one.
她被弄得感觉自己像是头号公敌。

Terrorism is the public enemy number one. Governments should work together to stop it.
恐怖主义是头号公敌。各国政府应当联合行动，以制止恐怖主义。