inconstancy vs faithlessness

inconstancy and faithlessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
inconstancy	Yes	No	No	No
faithlessness	Yes	No	No	No

As nouns, inconstancy and faithlessness are synonyms defined as:

inconstancy and faithlessness: unfaithfulness by virtue of being unreliable or treacherous

Other synonyms of inconstancy include falseness, fickleness.

inconstancy (noun)	faithlessness (noun)
the quality of being changeable and variable	unfaithfulness by virtue of being unreliable or treacherous
unfaithfulness by virtue of being unreliable or treacherous