richness vs copiousness

richness and copiousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
richness	Yes	No	No	No
copiousness	Yes	No	No	No

As nouns, copiousness is a hypernym of richness; that is, copiousness is a word with a broader meaning than richness:

Other hypernyms of richness include abundance, teemingness.

richness (noun)	copiousness (noun)
a strong deep vividness of hue	the property of a more than adequate quantity or supply
the property of a sensation that is rich and pleasing
the property of producing abundantly and sustaining vigorous and luxuriant growth
the property of being extremely abundant
splendid or imposing in size or appearance
the quality of having high intrinsic value
abundant wealth