彼の説明は不明確で、何を言いたいのか分からなかった。
His explanation was unclear, and I couldn't tell what he was trying to say.
責任の所在が不明確なまま、計画が進められた。
The plan went ahead with it still unclear who was responsible.
契約書の不明確な点は、署名する前に確認しておくべきだ。
You should check any vague points in the contract before signing it.