opacity vs opaque

opacity is a noun but opaque is not a noun.

Word	Noun	Adjective	Verb	Adverb
opacity	Yes	No	No	No
opaque	No	Yes	No	No

opacity (noun)	opaque (noun)
the quality of being opaque to a degree; the degree to which something reduces the passage of light
incomprehensibility resulting from obscurity of meaning
the phenomenon of not permitting the passage of electromagnetic radiation

opacity (adjective)	opaque (adjective)
	not transmitting or reflecting light or radiant energy; impenetrable to sight
	hard or impossible to understand