doubtful

And it’s not clear if feeling doubtful necessarily caused people to be more willing to take action, or if the two correlate for other reasons.

Whether Nato would ever consider such a move is highly doubtful.

And given our habit of quickly moving on from talking about war, it’s doubtful many of us would even remember just how much supporting Ukraine cost us.

Bacteriophages were developed over much of the 20th century by dedicated scientists who battled not just microbes but also doubtful colleagues and corrupt politics.

To be fair to Tapper, it's doubtful he's genuinely surprised at Johnson's priorities.