meanness vs pettiness

meanness and pettiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
meanness	Yes	No	No	No
pettiness	Yes	No	No	No

As nouns, pettiness is a hyponym of meanness; that is, pettiness is a word with a more specific, narrower meaning than meanness:

Other hyponyms of meanness include littleness, smallness, miserliness.

meanness (noun)	pettiness (noun)
the quality of being deliberately mean	the quality of being unimportant and petty or frivolous
extreme stinginess	lack of generosity in trifling matters
	narrowness of mind or ideas or views