doubtful
Americanadjective
-
of uncertain outcome or result.
- Synonyms:
- problematic, dubious, indecisive, unsettled, undetermined
- Antonyms:
- certain
-
admitting of or causing doubt; uncertain; ambiguous.
- Synonyms:
- indeterminate, unsure
- Antonyms:
- certain
-
unsettled in opinion or belief; undecided; hesitating.
- Synonyms:
- hesitant, vacillating, irresolute
-
of equivocal or questionable character.
His tactics are highly doubtful.
- Synonyms:
- shady
adjective
-
unlikely; improbable
-
characterized by or causing doubt; uncertain
a doubtful answer
-
unsettled; unresolved
-
of questionable reputation or morality
-
having reservations or misgivings
-
(of a sportsperson) not likely to be fit enough to play or take part
noun
-
a person who is undecided or uncertain about an issue
-
a sportsperson who is not likely to be fit enough to play or take part
Usage
See doubt.
It was formerly considered correct to use whether after doubtful (it is doubtful whether he will come), but now if and that are also acceptable
Related Words
Doubtful, dubious, incredulous, skeptical imply reluctance or unwillingness to be convinced. To be doubtful about something is to feel that it is open to question or that more evidence is needed to prove it: to be doubtful about the statements of witnesses. Dubious implies vacillation, unsureness, or suspicion: dubious about suggested methods of manufacture. Incredulous means unwilling or reluctant to believe: incredulous at the good news. Skeptical implies a general disposition to doubt or question: skeptical of human progress.
Other Word Forms
Etymology
Origin of doubtful
First recorded in 1350–1400, doubtful is from the Middle English word douteful. See doubt, -ful
Explanation
When you're doubtful about something, you're not sure about it. You might feel doubtful about the picnic you've planned if the forecast calls for torrential rain. Whether you're uncertain, undecided, or suspicious, you can describe yourself as doubtful. You'll be doubtful about your taxi driver's sense of direction when you pass the same building for the third time. You might also be doubtful about whether or not to try skydiving. Doubtful means "full of doubt," and doubt is from the Old French doter, "doubt or be afraid," with a Latin root, dubitare, "to question, hesitate, or waver in opinion."
Vocabulary lists containing doubtful
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
It’s highly doubtful this will happen, he said.
From MarketWatch • Apr. 18, 2026
Tariq Shaukat, CEO of code-verification company Sonar, said he’s doubtful AI is replacing most of the people losing jobs.
From The Wall Street Journal • Apr. 16, 2026
It is doubtful that Liam Gallagher will turn up at the ceremony in Los Angeles this November, having previously declared that he wasn't interested in receiving an award from "some geriatric in a cowboy hat".
From BBC • Apr. 13, 2026
It’s doubtful AI will flop as spectacularly as the metaverse did, if only because so many companies, universities, and governments are so vested in its success.
From Barron's • Mar. 19, 2026
Gimli took up one of the cakes and looked at it with a doubtful eye.
From "The Fellowship of the Ring" by J.R.R. Tolkien
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
