plea bargaining vs plea-bargain

plea bargaining is a noun but plea-bargain is not a noun.

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

plea bargaining (noun)	plea-bargain (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

plea bargaining (verb)	plea-bargain (verb)
	agree to plead guilty in return for a lesser charge