inadvertency vs heedlessness

inadvertency and heedlessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
inadvertency	Yes	No	No	No
heedlessness	Yes	No	No	No

As nouns, inadvertency and heedlessness are synonyms defined as:

inadvertency and heedlessness: the trait of forgetting or ignoring your responsibilities

Other synonyms of inadvertency include inadvertence, unmindfulness.

inadvertency (noun)	heedlessness (noun)
the trait of forgetting or ignoring your responsibilities	the trait of forgetting or ignoring your responsibilities
	the trait of acting rashly and without prudence
	a lack of attentiveness (as to children or helpless people)