forgetfulness vs unknowingness

forgetfulness and unknowingness both are nouns.

Word	Noun	Adjective	Verb	Adverb
forgetfulness	Yes	No	No	No
unknowingness	Yes	No	No	No

As nouns, unknowingness is a hypernym of forgetfulness; that is, unknowingness is a word with a broader meaning than forgetfulness:

forgetfulness: unawareness caused by neglectful or heedless failure to remember
unknowingness: unconsciousness resulting from lack of knowledge or attention

Other hypernyms of forgetfulness include unawareness.

forgetfulness (noun)	unknowingness (noun)
tendency to forget	unconsciousness resulting from lack of knowledge or attention
unawareness caused by neglectful or heedless failure to remember	ignorance (especially of orthodox beliefs)