plea bargaining vs bargaining

plea bargaining and bargaining both are nouns.

Word	Noun	Adjective	Verb	Adverb
plea bargaining	Yes	No	No	No
bargaining	Yes	No	No	No

As nouns, bargaining is a hypernym of plea bargaining; that is, bargaining is a word with a broader meaning than plea bargaining:

plea bargaining: (criminal law) a negotiation in which the defendant agrees to enter a plea of guilty to a lesser charge and the prosecutor agrees to drop a more serious charge
bargaining: the negotiation of the terms of a transaction or agreement

plea bargaining (noun)	bargaining (noun)
(criminal law) a negotiation in which the defendant agrees to enter a plea of guilty to a lesser charge and the prosecutor agrees to drop a more serious charge	the negotiation of the terms of a transaction or agreement