noun
a great many words; a huge number of words
A yojijukugo (four-character idiom) meaning an immense quantity of words or talk. Often used in contexts of lengthy explanations, verbose writing, or endless chatter.
彼の説明は千言万語に及んだが、結局何が言いたいのかわからなかった。
His explanation went on for a great many words, but in the end I couldn't understand what he wanted to say.
千言万語を費やすよりも、一言で要点を伝えるほうが効果的だ。
Rather than spending a huge number of words, it's more effective to convey the point in a single phrase.