知根知底 (zhī) — to know someone thoroughly / to be very familiar with someone's background

Definition

An idiom meaning you know someone thoroughly — their background, character, and history. Implies a long-standing, intimate familiarity, stronger than simply 认识.

idiom
to know someone thoroughly / to be very familiar with someone's background

Examples

  • 知根知底
    Wǒ men shì lǎo péng you le, hù xiāng zhī.
    We're old friends; we know each other inside out.
  • 知根知底
    Tā zài zhè jiā gōng sī gān le èr shí nián, duì měi gè yuán gōng dōu zhī.
    He's worked at this company for twenty years and knows every employee thoroughly.
  • 知根知底
    Bié zài tā miàn qián sā huǎng, tā zhī, nǐ piàn bù liǎo tā.
    Don't lie in front of him — he knows you too well, you can't fool him.

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