doubt vs doubtfulness

doubt and doubtfulness both are nouns.

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

As nouns, doubt and doubtfulness are synonyms defined as:

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

Other synonyms of doubt include dubiousness, question.

As nouns, doubt and doubtfulness are synonyms defined as:

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

doubt (noun)	doubtfulness (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

doubt (verb)	doubtfulness (verb)
consider unlikely
lack confidence in