adequacy vs adequateness

adequacy and adequateness both are nouns.

Word	Noun	Adjective	Verb	Adverb
adequacy	Yes	No	No	No
adequateness	Yes	No	No	No

As nouns, adequacy and adequateness are synonyms defined as:

adequacy and adequateness: the quality of being able to meet a need satisfactorily:

adequacy (noun)	adequateness (noun)
the quality of being able to meet a need satisfactorily:	the quality of being able to meet a need satisfactorily:
the quality of being sufficient for the end in view