fidelity vs unfaithful

fidelity is a noun but unfaithful is not a noun.

Word	Noun	Adjective	Verb	Adverb
fidelity	Yes	No	No	No
unfaithful	No	Yes	No	No

fidelity (noun)	unfaithful (noun)
the quality of being faithful
accuracy with which an electronic system reproduces the sound or image of its input signal

fidelity (adjective)	unfaithful (adjective)
	not true to duty or obligation or promises
	having sexual relations with someone other than your husband or wife, or your boyfriend or girlfriend
	having the character of, or characteristic of, a traitor
	not trustworthy