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
- doubtfully adverb
- doubtfulness noun
- predoubtful adjective
- predoubtfully adverb
- quasi-doubtful adjective
- quasi-doubtfully adverb
- undoubtful adjective
- undoubtfully adverb
- undoubtfulness noun
Etymology
Origin of doubtful
First recorded in 1350–1400, doubtful is from the Middle English word douteful. See doubt, -ful
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.
Treasury yield curve would steepen through 2026, widely accepted by a net 80% of respondents in February, is now more doubtful with only 56% viewing that as likely now.
From MarketWatch • Mar. 17, 2026
“It’s doubtful that the Fed would hike rates to address inflation worries that result from a spike in oil prices,” said Jack Janasiewicz, lead portfolio strategist at Natixis Investment Managers Solutions.
From Barron's • Mar. 3, 2026
Even if the air strikes succeed in ousting the regime, either by killing its leaders or forcing them to flee, it is doubtful the successors will be any friendlier to the West.
From Slate • Feb. 28, 2026
Some analysts are more doubtful of Iran’s capabilities.
From The Wall Street Journal • Feb. 27, 2026
Often the wizard consulted him at points where the choice of way was doubtful; but it was always Gandalf who had the final word.
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.