You could say that someone is not the sharpest knife in the drawer, not the sharpest knife in the drawer.

你可以说某人可能还不太行。

You're not the sharpest knife in the drawer, Pops.

老爷子 你的脑子还转的不够快啊。

So when we say " he's not the sharpest knife in the drawer" , we're not saying he's actually a knife, you can cut him, but he's not particularly intelligent compared to others perhaps.

所以当我们说 he's not the sharpest knife in the drawer 的时候，我们并不是说他实际上是一把刀，你可以砍他，但也许和其他人相比，他并不是特别聪明。