nark vs blabber

nark and blabber both are nouns.

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

As nouns, blabber is a hypernym of nark; that is, blabber is a word with a broader meaning than nark:

nark: an informer or spy working for the police
blabber: one who reveals confidential information to the police or other authority

Other hypernyms of nark include betrayer, informer, rat, squealer.

nark (noun)	blabber (noun)
an informer or spy working for the police	one who reveals confidential information to the police or other authority
a lawman concerned with narcotics violations

nark (verb)	blabber (verb)
inform or spy (for the police)	speak (about unimportant matters) rapidly and incessantly
cause annoyance in; disturb, especially by minor irritations