fidelity vs trueness

fidelity and trueness both are nouns.

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

As nouns, trueness is a hyponym of fidelity; that is, trueness is a word with a more specific, narrower meaning than fidelity:

Other hyponyms of fidelity include constancy, dedication, loyalty.

fidelity (noun)	trueness (noun)
the quality of being faithful	exactness of adjustment
accuracy with which an electronic system reproduces the sound or image of its input signal	the quality of being loyal
	conformity to reality or actuality