business deal vs dealing

business deal and dealing both are nouns.

Word	Noun	Adjective	Verb	Adverb
business deal	Yes	No	No	No
dealing	Yes	No	No	No

As nouns, dealing is a hypernym of business deal; that is, dealing is a word with a broader meaning than business deal:

business deal: a particular instance of buying or selling
dealing: the act of transacting within or between groups (as carrying on commercial activities)

Other hypernyms of business deal include dealings, transaction.

business deal (noun)	dealing (noun)
a particular instance of buying or selling	method or manner of conduct in relation to others
	the act of transacting within or between groups (as carrying on commercial activities)