老底 (lǎodǐ): one's past history

Meanings

Tā yī kāikǒu jiù jiē le duìfāng de lǎodǐ.

As soon as he opened his mouth, he exposed the other person's past.

Tā yīzhí zài yǐnmán zìjǐ de lǎodǐ.

She has been hiding her past all along.

Bié yǐwéi wǒ bù zhīdào nǐ de lǎodǐ!

Don't think I don't know your real story!

usage

老底 is colloquial and often used in the phrase 揭老底 (jiē lǎodǐ) — to expose or reveal someone's past secrets or embarrassing history.

老 lǎo

底 dǐ