receptivity vs receptiveness

receptivity and receptiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
receptivity	Yes	No	No	No
receptiveness	Yes	No	No	No

As nouns, receptivity and receptiveness are synonyms defined as:

receptivity and receptiveness: willingness or readiness to receive (especially impressions or ideas)

Other synonyms of receptivity include openness.

receptivity (noun)	receptiveness (noun)
willingness or readiness to receive (especially impressions or ideas)	willingness or readiness to receive (especially impressions or ideas)