band together vs confederate

band together is not a noun while confederate is a noun.

Word	Noun	Adjective	Verb	Adverb
band together	No	No	Yes	No
confederate	Yes	Yes	Yes	No

As verbs, band together and confederate are synonyms defined as:

band together (noun)	confederate (noun)
	a person who joins with another in carrying out some plan (especially an unethical or illegal plan)
	someone who assists in a plot

band together (adjective)	confederate (adjective)
	united in a confederacy or league

band together (verb)	confederate (verb)
form a group or unite	form a group or unite
	form a confederation with; of nations