negativeness vs negativism

negativeness and negativism both are nouns.

Word	Noun	Adjective	Verb	Adverb
negativeness	Yes	No	No	No
negativism	Yes	No	No	No

As nouns, negativeness and negativism are synonyms defined as:

negativeness and negativism: characterized by habitual skepticism and a disagreeable tendency to deny or oppose or resist suggestions or commands

Other synonyms of negativeness include negativity.

negativeness (noun)	negativism (noun)
characterized by habitual skepticism and a disagreeable tendency to deny or oppose or resist suggestions or commands	characterized by habitual skepticism and a disagreeable tendency to deny or oppose or resist suggestions or commands
an amount less than zero
the character of the negative electric pole