slang vs blackguard

slang and blackguard both are nouns.

Word	Noun	Adjective	Verb	Adverb
slang	Yes	No	Yes	No
blackguard	Yes	No	Yes	No

As verbs, blackguard is a hypernym of slang; that is, blackguard is a word with a broader meaning than slang:

Other hypernyms of slang include abuse, clapperclaw, shout.

slang (noun)	blackguard (noun)
a characteristic language of a particular group (as among thieves)	someone who is morally reprehensible
informal language consisting of words and expressions that are not considered appropriate for formal occasions; often vituperative or vulgar

slang (verb)	blackguard (verb)
abuse with coarse language	use foul or abusive language towards
fool or hoax	subject to laughter or ridicule
use slang or vulgar language