mercantile law vs law merchant

mercantile law and law merchant both are nouns.

Word	Noun	Adjective	Verb	Adverb
mercantile law	Yes	No	No	No
law merchant	Yes	No	No	No

As nouns, mercantile law and law merchant are synonyms defined as:

mercantile law and law merchant: the body of rules applied to commercial transactions; derived from the practices of traders rather than from jurisprudence

Other synonyms of mercantile law include commercial law.

mercantile law (noun)	law merchant (noun)
the body of rules applied to commercial transactions; derived from the practices of traders rather than from jurisprudence	the body of rules applied to commercial transactions; derived from the practices of traders rather than from jurisprudence