openness vs willingness

openness and willingness both are nouns.

Word	Noun	Adjective	Verb	Adverb
openness	Yes	No	No	No
willingness	Yes	No	No	No

As nouns, willingness is a hypernym of openness; that is, willingness is a word with a broader meaning than openness:

openness: willingness or readiness to receive (especially impressions or ideas)
willingness: cheerful compliance

openness (noun)	willingness (noun)
characterized by an attitude of ready accessibility (especially about one's actions or purposes); without concealment; not secretive	cheerful compliance
willingness or readiness to receive (especially impressions or ideas)
without obstructions to passage or view