“勒索”常见的英文表达是 blackmail ，它既可以作名词，也可以作动词。
意为“勒索；敲诈；勒索所得的款项”，例如：
He was accused of blackmail.（他被指控犯有勒索罪。）
The gang demanded a large sum of money as blackmail.（这伙歹徒索要一大笔钱作为勒索金。）
意为“对……进行勒索；敲诈；胁迫”，例如：
They tried to blackmail him into giving them the money.（他们试图敲诈他，让他把钱交出来。）
She was blackmailed by someone who threatened to reveal her secret.（有人威胁要揭露她的秘密，对她进行勒索。）