Merchantman vs Businessman - What's the difference?

As nouns the difference between merchantman and businessman

is that merchantman is merchant while businessman is a man in business, one who works at a commercial institution.

(merchantmen)

(obsolete) merchant

a cargo ship -- engaged in commercial activities, as opposed to a warship

(wikipedia businessman)

(businessmen)

a man in business, one who works at a commercial institution

* businessperson