doubtful

IPA/ˈdaʊtfl/
KK[dˈaʊtfəl]IPA/ˈdaʊtfl/

doubtful — adjective

  • doubtfulpositive
  • more doubtfulcomparative
  • most doubtfulsuperlative

1. feeling uncertain or lacking confidence about something because you do not have

1.adjectiveB1
Definition

feeling uncertain or lacking confidence about something because you do not have enough information or a clear opinion about it

Example

Talia was doubtful about accepting the job because she knew little about the company.

doubtful about + gerund

The doctors felt doubtful whether the new drug would help patients with a rare condition.

felt doubtful whether + clause

Common collocations
  • doubtful about
  • doubtful whether
  • doubtful if
  • doubtful that
  • feel doubtful
  • look doubtful
  • remain doubtful
  • seem doubtful
Synonyms
  • uncertain

    The broadest term; covers any lack of certainty without the questioning tone of doubtful

  • unsure

    Focuses on a person's lack of confidence in their own judgement or knowledge

  • skeptical

    Stronger than doubtful; implies a tendency to disbelieve or demand proof

  • hesitant

    Describes reluctance to act, which may stem from doubt but is not the same as mental uncertainty

Antonyms
  • certain

    Having complete confidence or knowledge

  • confident

    Feeling sure about one's own ability or judgement

  • convinced

    Having been persuaded to accept something as true

Grammar Patterns

be doubtful about + noun/gerund

be doubtful whether/if + clause

be doubtful that + clause

Usage Note

Subject is usually a person. The uncertainty concerns a specific matter (introduced by about, whether, if, or that), not a general state of mind. Common with linking verbs such as feel, look, seem, and remain.

Common Mistakes

I am doubtful to join the trip.
I am doubtful about joining the trip.
'doubtful' takes 'about' before a gerund, not a to-infinitive.
She is doubtful for the exam results.
She is doubtful about the exam results.
Use 'about', not 'for', to introduce the topic of uncertainty.

2. not likely to happen, succeed, or be true; uncertain in outcome or result

2.adjectiveB2
Definition

not likely to happen, succeed, or be true; uncertain in outcome or result

Example

The outcome of the election remained doubtful until the very last votes were counted.

outcome remained doubtful

It is doubtful whether the old bridge can survive another harsh winter without major repairs.

It is doubtful whether + clause

Common collocations
  • it is doubtful whether/that
  • outcome / result / future / success is doubtful
  • looks / remains / seems doubtful
  • highly doubtful
Synonyms
  • unlikely

    More direct and common; focuses purely on probability without the uncertainty nuance

  • improbable

    Slightly more formal and suggests a lower probability than unlikely

  • questionable

    Carries a judgement of quality or validity rather than pure probability

  • uncertain

    Broader term; can describe any situation with an unknown outcome

Antonyms
  • likely

    Having a high probability of happening

  • certain

    Definite; known to be true or to happen

  • assured

    Guaranteed or confidently expected to happen

Grammar Patterns

It is doubtful whether + clause

It is doubtful that + clause

Subject + looks/remains/seems doubtful

Usage Note

The subject is a situation, outcome, plan, or possibility — NOT a person. Frequently appears in the impersonal construction 'it is doubtful whether/that + clause' to express a low probability. Compare with sense 1, where the subject is a person feeling uncertain.

Common Mistakes

I am doubtful that it will rain.' (when referring to the weather)
It is doubtful that it will rain.
Use the impersonal 'it' construction when the subject is the situation, not a person.
The game's success is doubtable.
The game's success is doubtful.
'Doubtful' is the standard adjective; 'doubtable' is very rare and not used in natural English.

Word family

Synonym discussion

Sense: adjective/1

Uncertain is the broadest of these words, covering any situation where information is incomplete. Unsure focuses on a person's inner lack of confidence in their own knowledge or opinion. Doubtful adds a stronger tone of questioning the reliability of something — not just lacking information, but actively doubting it. Skeptical goes further still, implying a habit of doubt or a demand for strong proof before believing. Hesitant describes reluctance to act that may come from doubt, but it is about behaviour rather than a state of mind. For example: 'She was uncertain about the date' (lacks information); 'She was doubtful about his explanation' (suspects it might be wrong); 'She was skeptical of the claim' (wants evidence); 'She was hesitant to sign' (held back by doubt).

uncertain ↗unsure ↗skeptical ↗hesitant ↗

Common collocations

Adverbs

Etymology

LatinFrenchEnglish

Doubtful was formed in English by adding the suffix -ful (meaning 'full of') to the noun doubt, which came into English from Old French 'douter' (to doubt), itself from Latin 'dubitare' (to waver in opinion, to be uncertain). The word originally meant 'full of doubt' and has been used since the 14th century.