as sharp as a razor 机警；厉害

【例句】
The fellow is as sharp as a razor. Be careful in your dealings with him.
这家伙厉害得很，你和他打交道时要特别小心。

This young man is as sharp as a razor. I am sure he will reach a high position in the company.
这个年轻人非常机灵。我相信他在公司会升到很高职位的。