闲磨牙

Traditional (Taiwan): 閒磨牙

xiánmóyá ㄒㄧㄢˊ ㄇㄛˊ ㄧㄚˊ

    • to argue pointlessly
    • to talk idle nonsense

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
idly grind teeth
Meaning
To argue pointlessly or talk idle nonsense. Mildly dismissive.

Sources