faultiness vs bugginess

faultiness and bugginess both are nouns.

Word	Noun	Adjective	Verb	Adverb
faultiness	Yes	No	No	No
bugginess	Yes	No	No	No

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

Other hyponyms of faultiness include lameness, sickness, dysfunctionality.

faultiness (noun)	bugginess (noun)
the state of being defective	the state of having bugs