oppressiveness vs oppression

oppressiveness and oppression both are nouns.

Word	Noun	Adjective	Verb	Adverb
oppressiveness	Yes	No	No	No
oppression	Yes	No	No	No

As nouns, oppressiveness and oppression are synonyms defined as:

oppressiveness (noun)	oppression (noun)
unwelcome burdensome difficulty	the act of subjugating by cruelty
a feeling of being oppressed	a feeling of being oppressed
	the state of being kept down by unjust use of force or authority: