to begin with vs earlier

to begin with is not an adjective while earlier is an adjective.

Word	Noun	Adjective	Verb	Adverb
to begin with	No	No	No	Yes
earlier	No	Yes	No	Yes

As adverbs, to begin with and earlier are synonyms defined as:

Other synonyms of to begin with include in the beginning, in the first place, originally.

to begin with (adjective)	earlier (adjective)
	(comparative and superlative of `early') more early than; most early

to begin with (adverb)	earlier (adverb)
before now	earlier in time; previously
	comparatives of `soon' or `early'
	before now