business deal vs transaction

business deal and transaction both are nouns.

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

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

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

Other hypernyms of business deal include dealing, dealings.

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