adverb
mumblingly; mutteringly; unintelligibly
Describes speaking in a low, unclear, or muffled manner, often because the speaker is embarrassed, unsure, or trying to avoid being overheard. Frequently used with verbs like 言う or 話す.
彼は何かごにょごにょ言っていたが、よく聞こえなかった。
He was mumbling something, but I couldn't hear it well.
質問に答えるとき、彼女はごにょごにょと話
When answering the question, she started speaking unintelligibly.
Onomatopoeic or mimetic word; the exact derivation is uncertain, but it imitates the sound of low, indistinct murmuring.