An onomatopoeic adverb meaning to mutter or mumble complaints under one's breath.
彼は会議中にぐちぐち小声で文句を言っていた。
He was muttering complaints under his breath during the meeting.
失敗してからずっとぐちぐち言っている。
He's been mumbling and complaining ever since the failure.
朝からぐちぐちと不満を漏らすのはやめてください。
Please stop grumbling all morning.
An adverb meaning to complain continuously or nag about something persistently.
彼女はいつもぐちぐち不満を言って、聞いている方が疲れる。
She is always complaining continuously; it's tiring to listen.
ぐちぐち言わずに、まず行動してみたらどうだろうか。
Instead of complaining continuously, why not try acting first?
上司に対してぐちぐち言うのは良くない。
It's not good to keep complaining to your boss.