Dictionary / Vocabulary / 愚痴をこぼす
ぐちをこぼす
to whinge; to kvetch; to gripe; to complain
Also written 愚痴を零す、愚痴を溢す
彼は酒を飲むと、息子の愚痴をこぼすのがお決まりだ。
He never drinks without complaining about his son.