expertness vs expertise

expertness and expertise both are nouns.

Word	Noun	Adjective	Verb	Adverb
expertness	Yes	No	No	No
expertise	Yes	No	No	No

As nouns, expertness and expertise are synonyms defined as:

expertness and expertise: skillfulness by virtue of possessing special knowledge

expertness (noun)	expertise (noun)
skillfulness by virtue of possessing special knowledge	skillfulness by virtue of possessing special knowledge