neglect vs remissness

neglect and remissness both are nouns.

Word	Noun	Adjective	Verb	Adverb
neglect	Yes	No	Yes	No
remissness	Yes	No	No	No

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

Other hyponyms of neglect include delinquency, dereliction, willful neglect, laxity, laxness, slackness.

neglect (noun)	remissness (noun)
failure to act with the prudence that a reasonable person would exercise under the same circumstances	the quality of being lax and neglectful
willful lack of care and attention
the trait of neglecting responsibilities and lacking concern
lack of attention and due care
the state of something that has been unused and neglected

neglect (verb)	remissness (verb)
leave undone or leave out
give little or no attention to
fail to attend to
fail to do something; leave something undone