expeditiousness vs rapidness

expeditiousness and rapidness both are nouns.

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

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

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

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