doubtfulness vs dubiousness

doubtfulness and dubiousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
doubtfulness	Yes	No	No	No
dubiousness	Yes	No	No	No

As nouns, doubtfulness and dubiousness are synonyms defined as:

doubtfulness and dubiousness: uncertainty about the truth or factuality or existence of something

Other synonyms of doubtfulness include doubt, question.

As nouns, doubtfulness and dubiousness are synonyms defined as:

Other synonyms of doubtfulness include doubt, dubiety, incertitude, uncertainty.

doubtfulness (noun)	dubiousness (noun)
uncertainty about the truth or factuality or existence of something	uncertainty about the truth or factuality or existence of something
the state of being unsure of something	the state of being unsure of something