scolding; faultfinding; nagging
Refers to persistent, often petty verbal criticism or nagging, typically in personal relationships.
母の口小言にはもううんざりだ。
I'm fed up with my mother's constant nagging.
彼は妻の口小言を気にしていないようだ。
He doesn't seem to mind his wife's faultfinding.
Compound of 口 (mouth, speech) and 小言 (scolding, complaint). The exact historical derivation is uncertain, but the combination reinforces the idea of verbal nagging.