informal vocabulary that is composed typically of new words or meanings, impolite or vulgar references, etc, and that belongs to familiar conversation rather than written language

In the detestable slang of the day we were now both ‘at a deadlock’ — Wilkie Collins

language peculiar to a particular group; argot or jargon

prison slang

(used before a noun) of or belonging to such vocabulary or language

a slang term

informal to abuse (somebody) with harsh or coarse language

The two drivers were slanging each other

informal to use harsh or vulgar abusive language