doubtful

American  

[dout-fuhl] / ˈdaʊt fəl /

adjective

1. of uncertain outcome or result.

   Synonyms:

   problematic, dubious, indecisive, unsettled, undetermined

   Antonyms:

   certain

2. admitting of or causing doubt; uncertain; ambiguous.

   Synonyms:

   indeterminate, unsure

   Antonyms:

   certain

3. unsettled in opinion or belief; undecided; hesitating.

   Synonyms:

   hesitant, vacillating, irresolute

4. of equivocal or questionable character.

   His tactics are highly doubtful.

   Synonyms:

   shady

---

doubtful British  

/ ˈdaʊtfʊl /

adjective

1. unlikely; improbable

2. characterized by or causing doubt; uncertain

   a doubtful answer

3. unsettled; unresolved

4. of questionable reputation or morality

5. having reservations or misgivings

6. (of a sportsperson) not likely to be fit enough to play or take part

---

noun

1. a person who is undecided or uncertain about an issue

2. 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

Synonym Usage

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

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."

Example Sentences

“You reveled in his company. He filled you with energy and humor when you felt doubtful and weak,” said Anna Wintour, the global editorial director of Vogue and Conde Nast’s chief content officer.

From Los Angeles Times • May 27, 2026

Collett rejected this, and said "it is doubtful that vigorous children and teenagers would take much notice".

From BBC • May 6, 2026

"It seems doubtful to me that either can control AI."

From Barron's • Apr. 24, 2026

The company is so “heavily embedded” in the modern landscape, he said, and he’s doubtful that will change even as new technologies emerge.

From MarketWatch • Apr. 1, 2026

Percy looked doubtful, but he touched the cap to the hilt of the sword.

From "The House of Hades" by Rick Riordan

Related Words

• debatable
• dicey
• dubious
• hazy
• indecisive
• insecure
• precarious
• problematic
• suspicious
• uncertain
• undecided
• uneasy
• unsettled
• unstable
• unsure