primarily vs in the main

primarily and in the main both are adverbs.

Word	Noun	Adjective	Verb	Adverb
primarily	No	No	No	Yes
in the main	No	No	No	Yes

As adverbs, primarily and in the main are synonyms defined as:

Other synonyms of primarily include chiefly, mainly, principally.

primarily (adverb)	in the main (adverb)
of primary import	without distinction of one from others
for the most part	for the most part