Word Type

Adjective

Adjective

Noun

The word "doubtful" can be used as adjective, adjective and noun.

Word Relationships

Derived Terms

Doubtful Creek doubtfully doubtfulness undoubtful

Derived From

doubt ful

Distinct From

doubtless

Related Terms

ambiguous causing character doubt doubting dreadful dubious enigmatical equivocal fearsome hazardous hesitating improbable indeterminate obscure outcome problematical questionable sceptical showing suspicious uncertain unclear undecided undetermined unlikely unquestioned unreliable unsure wavering

Similar Terms

incertain questionable uncertain uncertain unsettled unsure

Synonym Network

in question tentative

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.