squealer vs nark

squealer and nark both are nouns.

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

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

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

squealer (noun)	nark (noun)
domestic swine	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

squealer (verb)	nark (verb)
	inform or spy (for the police)
	cause annoyance in; disturb, especially by minor irritations