dubious

dubious — adjective

1. describes a claim, statement, method, or situation that makes you doubt its trut

1.adjectiveB2
Definition

describes a claim, statement, method, or situation that makes you doubt its truth, honesty, or quality — for example, a business deal that seems too good to be true or a scientific result that cannot be confirmed.

Example

The company's claims about the product seemed highly dubious to the government inspectors.

collocation: highly dubious

Min received a dubious honour — the prize for the employee with the most typing errors.

ironic use: dubious honour / dubious distinction

Common collocations
  • dubious honour/distinction
  • dubious claim/statement
  • dubious methods/practices
  • dubious origin/provenance
  • dubious quality
Synonyms
  • questionable

    slightly weaker — suggests room for doubt rather than strong suspicion; e.g. questionable decision vs dubious methods

  • suspicious

    implies active distrust or belief that something is wrong; stronger in moral judgment

  • doubtful

    more neutral; can mean 'unlikely' about outcomes, while dubious carries a quality/trust judgment

Antonyms
  • reliable

    trustworthy and able to be believed

  • credible

    able to be believed; convincing in a positive sense

Grammar Patterns

dubious + noun

be + dubious

Usage Note

Often used before a noun (attributive): a dubious claim, a dubious method. When used after a linking verb (be, seem, appear), the subject is usually abstract: His explanation seemed dubious. For the feeling of doubt in a person, see sense 2 (FEELING DOUBTFUL).

Common Mistakes

The story is very dubious for me.
The story seems highly dubious to me.
Use 'seems/looks/appears dubious' + 'to' for opinion, not 'for'.
I am dubious that he will come.
I am doubtful that he will come.
When expressing personal uncertainty about a future event, 'doubtful' is more natural; 'dubious' implies suspicion or moral questioning.

2. used about a person who is not sure whether something is right, true, or good, u

2.adjectiveB2
Definition

used about a person who is not sure whether something is right, true, or good, usually because a detail feels wrong or suspicious — for example, being dubious about a promise because the person has broken promises before.

Example

Heloísa was dubious about hiking up the mountain during a winter storm.

dubious about + [activity/plan]

Tunde felt dubious when a stranger offered to carry his shopping all the way home.

Common collocations
  • dubious about
  • dubious of
  • look dubious
  • remain dubious
  • feel dubious
Synonyms
  • doubtful

    more neutral and slightly weaker; can be used for probability (doubtful that it will rain) whereas dubious is not

  • skeptical

    more intellectual — involves questioning based on evidence or logic; common in academic, scientific contexts

  • uncertain

    broader — covers any lack of certainty, not necessarily with suspicion

Antonyms

Grammar Patterns

be + dubious + about + noun/gerund

feel/remain + dubious + about/of

Usage Note

This sense describes a person's state of mind, not the quality of a thing (for that, see sense 1, QUESTIONABLE). Common in patterns: dubious about + noun/gerund, dubious of + noun. Can also describe someone's facial expression or tone: She gave him a dubious look.

Common Mistakes

The plan is dubious.' (meaning the person is unsure)
I am dubious about the plan.
'dubious' alone on a thing refers to the thing being suspect (sense 1); for personal uncertainty, use 'dubious about' + the thing.
I am dubious if it rains tomorrow.
I am doubtful whether it will rain tomorrow.
'dubious' is not used for simple probability; use 'doubtful' for likelihood.

Word family

  • dubiously
    adverbC1
  • dubiousness
    nounC1
  • dubiety
    nounC2

Synonym discussion

Sense: adjective/1

All three words describe something that is not fully trustworthy or certain, but they differ in strength and nuance. 'Questionable' is the mildest — it simply raises doubts without strong judgment, as in a questionable decision or questionable taste. 'Dubious' carries a stronger sense of moral or quality suspicion: a dubious claim feels dishonest, not just uncertain. 'Suspicious' implies the most active distrust — you believe something may be wrong or illegal, as in suspicious behavior or suspicious circumstances. 'Doubtful' overlaps but is more neutral: a doubtful outcome means 'unlikely,' while a dubious outcome means 'of questionable quality or honesty.' Choose 'questionable' for polite uncertainty, 'dubious' for quality/trust concerns, 'suspicious' for wrongdoing, and 'doubtful' for probability. For example: 'Her taste in music is questionable, but the business deal is dubious, and the accounting practices are downright suspicious.'

questionable ↗suspicious ↗doubtful ↗

Common collocations

Adverbs

  • highly dubious
  • somewhat dubious
  • morally dubious
  • ethically dubious
  • legally dubious

Phrases

  • dubious honour of
  • dubious distinction of

Prepositions

  • dubious about
  • dubious of

Etymology

LatinFrenchEnglish

Comes from the Latin word 'dubius,' meaning 'wavering between two opinions' or 'doubtful.' It passed through Late Latin 'dubiosus' into Middle French 'dubieux,' and entered English in the mid-1500s. The sense of 'questionable quality or honesty' developed from the original idea of being uncertain about the truth of something.