onerousness vs oppressiveness

onerousness and oppressiveness both are nouns.

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

As nouns, onerousness and oppressiveness are synonyms defined as:

Other synonyms of onerousness include burdensomeness, heaviness.

onerousness (noun)	oppressiveness (noun)
unwelcome burdensome difficulty	unwelcome burdensome difficulty
	a feeling of being oppressed