doubtful

adjective

doubt·​ful ˈdau̇t-fəl 

1

a

: lacking a definite opinion, conviction, or determination

They were doubtful about the advantages of the new system.

b

: uncertain in outcome : undecided

The outcome of the election remains doubtful.

2

: marked by qualities that raise doubts about worth, honesty, or validity

of doubtful repute

3

: giving rise to doubt or uncertainty : open to question

It is doubtful that they ever knew what happened.

a doubtful premise

doubtfully

ˈdau̇t-fə-lē 

adverb

doubtfulness noun

Synonyms of doubtful

• unsure
• skeptical
• suspicious
• uncertain

Choose the Right Synonym for doubtful

doubtful, dubious, problematic, questionable mean not affording assurance of the worth, soundness, or certainty of something.

doubtful implies little more than a lack of conviction or certainty.

doubtful about whether I said the right thing

dubious stresses suspicion, mistrust, or hesitation.

dubious about the practicality of the scheme

problematic applies especially to things whose existence, meaning, fulfillment, or realization is highly uncertain.

whether the project will ever be finished is problematic

questionable may imply no more than the existence of doubt but usually suggests that the suspicions are well-grounded.

a man of questionable honesty

Examples of doubtful in a Sentence

I tried to reassure them, but they remained doubtful.

The truth of the statements was doubtful.

Their decisions were based on data of doubtful accuracy.

Recent Examples on the Web

Former University of Denver Pioneers star and Denver native Troy Terry (upper-body injury) also sounded doubtful. —Andrew Knoll, Oc Register, 20 Jan. 2026

Coach Marco Sturm did term Peeke as doubtful, but the defenseman was happy to get on the ice. —Steve Conroy, Boston Herald, 17 Jan. 2026

The Mavericks have listed the rookie as doubtful on their latest injury report ahead of Saturday’s game. —Sportsday Staff, Dallas Morning News, 16 Jan. 2026

Newsom, who is working behind the scenes with SEIU-UHW in an effort to stop the ballot measure, on Friday appeared doubtful that a deal could be struck with proponents of the measure. —Dakota Smith, Los Angeles Times, 16 Jan. 2026

Word History

Etymology

see doubt entry 1

First Known Use

14th century, in the meaning defined at sense 3

Kids Definition

doubtful

adjective

doubt·​ful ˈdau̇t-fəl 

1

: not clear or certain as to fact

a doubtful claim

2

: questionable sense 2

doubtful intentions

3

: undecided in opinion

4

: not certain in outcome

doubtfully

-fə-lē 

adverb

doubtfulness noun