doubtful

If someone looks at a complicated math problem with a furrowed brow and says, "Hmm, that seems doubtful," they mean they are not sure the solution is correct. Being doubtful means feeling uncertain or not fully believing something. It can be used for a plan, a statement, a promise, or even a weather forecast. You might feel doubtful about accepting an invitation if you already have other commitments.

The word often suggests a quiet voice inside that keeps asking questions. A detective investigating a crime might be doubtful about a witness's story, meaning they do not fully trust it. It can also mean that something is not very likely to happen, like snow falling in the middle of a tropical July.

To be doubtful means to feel uncertainty or to have trouble believing something. It is more than simply not knowing. The word usually carries a sense of hesitation, suspicion, or weak confidence. For example, if you say, "She was doubtful that he would keep his promise," you mean she was not convinced he would do it.

The word can describe both a person's state of mind and the quality of a thing. If you are doubtful, you are the one feeling unsure. If a claim, excuse, or story is called doubtful, it means it does not seem true or reliable. If someone is described as a "doubtful character," the idea is that people do not trust that person very much.

Another common use is about likelihood. In this sense, doubtful means "probably not" or "not likely." If a team says a player is doubtful for tomorrow's game, it usually means the player will probably not take part. In the same way, a plan with a doubtful chance of success is a plan that does not seem likely to work.

The strength of the feeling can vary. You might be only a little doubtful about whether you locked the back door, or strongly doubtful about a risky long-term plan. In everyday English, the word often sits close to unsure, skeptical, unlikely, and questionable, depending on the sentence. The core idea stays the same: something does not feel certain, convincing, or likely.