shoot the breeze vs discourse

shoot the breeze is not a noun while discourse is a noun.

Word	Noun	Adjective	Verb	Adverb
shoot the breeze	No	No	Yes	No
discourse	Yes	No	Yes	No

As verbs, discourse is a hypernym of shoot the breeze; that is, discourse is a word with a broader meaning than shoot the breeze:

Other hypernyms of shoot the breeze include converse.

shoot the breeze (noun)	discourse (noun)
	an extended communication (often interactive) dealing with some particular topic
	extended verbal expression in speech or writing
	an address of a religious nature (usually delivered during a church service)

shoot the breeze (verb)	discourse (verb)
talk socially without exchanging too much information	talk at length and formally about a topic
	carry on a conversation
	to consider or examine in speech or writing