unreliable; uncertain; indefinite; unclear
その情報は不確かだ。
That information is uncertain.
目撃者の証言は不確かで、信憑性に乏しい。
The witness's testimony was unreliable and lacked credibility.
天気予報が不確かで、旅行は危ぶまれた。
The weather forecast was uncertain, and the trip was called into question.