opposition vs oppositeness

opposition and oppositeness both are nouns.

Word	Noun	Adjective	Verb	Adverb
opposition	Yes	No	No	No
oppositeness	Yes	No	No	No

As nouns, opposition and oppositeness are synonyms defined as:

opposition (noun)	oppositeness (noun)
the act of hostile groups opposing each other	the relation between opposed entities
the action of opposing something that you disapprove or disagree with
a body of people united in opposing something
an armed adversary (especially a member of an opposing military force)
a contestant that you are matched against
a direction opposite to another
the relation between opposed entities