bunk off vs slang

bunk off is not a noun while slang is a noun.

Word	Noun	Adjective	Verb	Adverb
bunk off	No	No	Yes	No
slang	Yes	No	Yes	No

bunk off (noun)	slang (noun)
	a characteristic language of a particular group (as among thieves)
	informal language consisting of words and expressions that are not considered appropriate for formal occasions; often vituperative or vulgar

bunk off (verb)	slang (verb)
play truant from work or school	abuse with coarse language
	fool or hoax
	use slang or vulgar language