willful neglect vs negligence

willful neglect and negligence both are nouns.

Word	Noun	Adjective	Verb	Adverb
willful neglect	Yes	No	No	No
negligence	Yes	No	No	No

As nouns, negligence is a hypernym of willful neglect; that is, negligence is a word with a broader meaning than willful neglect:

Other hypernyms of willful neglect include neglect, neglectfulness.

willful neglect (noun)	negligence (noun)
a tendency to be negligent and uncaring	failure to act with the prudence that a reasonable person would exercise under the same circumstances
	the trait of neglecting responsibilities and lacking concern