doubtful

Doubtful is an adjective that describes a state of uncertainty or skepticism about something’s truth, value, or likelihood. It can refer to whether a claim is true, whether an event will occur, or whether a course of action is advisable. In everyday use, a sentence might say, “It is doubtful that the project will be completed on time” or “She sounded doubtful about the plan.” Synonyms include uncertain, questionable, and dubious; antonyms include certain and confident.

Etymology and form: Doubtful originates from Old French doute and Latin dubitare, meaning to hesitate. The suffix -ful forms an adjective meaning “full of doubt.” In certain contexts, the phrase “it is doubtful” appears common in formal or administrative language.

Grammatical use: Doubtful can take complements with that-clauses, as in “It is doubtful that he will attend,” or with whether-clauses, as in “It is doubtful whether he will attend.” It can also appear with nouns, as in “a doubtful source” or “a doubtful prospect.” The related adverb form, doubtfully, is used to describe how something is done, while a person or reaction may be described as looking or appearing doubtful.

Usage and nuance: In formal writing, doubt may be hedged to avoid overstatement when outcomes are uncertain. In casual speech, doubtful often communicates mild skepticism rather than outright disbelief. While similar to uncertain or questionable, doubtful can imply lower probability or credibility without invoking moral judgment; when stronger suspicion or ethical concern is intended, terms like dubious may be more appropriate.