不能不

bùnéngbù

phrase HSK 5 #13,624

Meanings

Double negative: 'cannot not' = 'must/have to'

Zhè jiàn shì wǒ bù néng bù guǎn.

I have to take care of this matter.

Nǐ bù néng bù chéngrèn tā shuō de yǒu dàolǐ.

You have to admit what he said makes sense.

Miànduì zhè zhǒng qíngkuàng, wǒ bù néng bù dānxīn.

Facing this situation, I cannot help but worry.

grammar

不能不 is a double negative that creates a strong affirmative meaning (must/have to). It's stronger than 必须 (bìxū) because it implies there's no choice.

usage

Similar double-negative patterns: 不得不 (bù dé bù, have no choice but to) and 不可不 (bù kě bù, must — more literary).

不 bù

能 néng