What is the meaning of slang?

noun

• Informal language consisting of words and expressions that are not considered appropriate for formal occasions; often vituperative or vulgar.
  • usage: "their speech was full of slang expressions"
  • synonyms: slang expression, slang term
• A characteristic language of a particular group (as among thieves. )
  • usage: "they don't speak our lingo"
  • synonyms: cant, jargon, lingo, argot, patois, vernacular

verb

• Use slang or vulgar language.
• Fool or hoax.
  • usage: "The immigrant was duped because he trusted everyone"; "You can't fool me"
  • synonyms: gull, dupe, befool, cod, fool, put on, take in, put one over, put one across
• Abuse with coarse language. .