nark vs inform

nark is a noun but inform is not a noun.

Word	Noun	Adjective	Verb	Adverb
nark	Yes	No	Yes	No
inform	No	No	Yes	No

As verbs, inform is a hypernym of nark; that is, inform is a word with a broader meaning than nark:

nark (noun)	inform (noun)
an informer or spy working for the police
a lawman concerned with narcotics violations

nark (verb)	inform (verb)
inform or spy (for the police)	give character or essence to
cause annoyance in; disturb, especially by minor irritations	impart knowledge of some fact, state of affairs, or event to
	act as an informer