一面之交

    yīmiànzhījiāo

    1. Idiomto have met once; casual acquaintance

    我们只是一面之交,不是很熟悉。Wǒmen zhǐshì yīmiànzhījiāo, bùshì hěn shúxī.We only have a passing acquaintance and aren't very familiar with each other.