monyo-monyo
Speaking so unclearly that the words blur together into mush. You know they're talking, but you can't make out a single word.
💡A student giving an excuse — 'He was monyo-monyo about why he was late.'
遅刻の理由をもにょもにょと言い訳した。
He explained his lateness monyo-monyo.
He was ___ something, but I couldn't understand a word.
何か○○と言っていたが、聞き取れなかった。