chumminess vs sociableness

chumminess and sociableness both are nouns.

Word	Noun	Adjective	Verb	Adverb
chumminess	Yes	No	No	No
sociableness	Yes	No	No	No

As nouns, sociableness is a hypernym of chumminess; that is, sociableness is a word with a broader meaning than chumminess:

chumminess: the quality of affording easy familiarity and sociability
sociableness: the relative tendency or disposition to be sociable or associate with one's fellows

Other hypernyms of chumminess include sociability.

chumminess (noun)	sociableness (noun)
the quality of affording easy familiarity and sociability	the relative tendency or disposition to be sociable or associate with one's fellows