钝

dāo dùn le

刀钝了。

The knife is blunt.

fǔ tou tài dùn kǎn bù dǎo shù

斧头太钝，砍不倒树。

The axe is too blunt to cut down the tree.

nǐ de dāo rèn yǒu diǎn dùn le

你的刀刃有点钝了。

I see your edge has dulled.

chí dùn

迟钝

dull-witted

wǒ nǎo zi xiàn zài yǒu diǎn dùn

我脑子现在有点钝。

My mind is a little bit slow now.

yú dùn

愚钝

stupid