smallness vs meanness

smallness and meanness both are nouns.

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

As nouns, meanness is a hypernym of smallness; that is, meanness is a word with a broader meaning than smallness:

smallness (noun)	meanness (noun)
the property of having a relatively small size	the quality of being deliberately mean
lack of generosity in trifling matters	extreme stinginess
the property of being a relatively small amount
the property of having relatively little strength or vigor
The quality of being minor in influence, power, or rank.