slang vs lingo

slang and lingo both are nouns.

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

As nouns, slang and lingo are synonyms defined as:

slang and lingo: a characteristic language of a particular group (as among thieves)

Other synonyms of slang include argot, cant, jargon, patois, vernacular.

slang (noun)	lingo (noun)
a characteristic language of a particular group (as among thieves)	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