知之为知之，不知为不知 — “To know what you know, and to admit what you don't know”

知之为知之，不知为不知 (zhī zhī wéi zhī zhī ， bù zhī wèi bù zhī) is a Chinese idiom (chengyu) meaning “to know what you know, and to admit what you don't know”.

知之为知之，不知为不知 is pronounced zhī zhī wéi zhī zhī ， bù zhī wèi bù zhī in Mandarin Chinese.

Literally, 知之为知之，不知为不知 means “to know that you know, and to know that you don't know”. It is used to mean “to know what you know, and to admit what you don't know”.

懂就是懂，不懂就是不懂。