expeditiousness vs rapidity

expeditiousness and rapidity both are nouns.

Word	Noun	Adjective	Verb	Adverb
expeditiousness	Yes	No	No	No
rapidity	Yes	No	No	No

As nouns, rapidity is a hypernym of expeditiousness; that is, rapidity is a word with a broader meaning than expeditiousness:

Other hypernyms of expeditiousness include celerity, quickness, rapidness, speediness.

expeditiousness (noun)	rapidity (noun)
the property of being prompt and efficient	a rate that is rapid