approximately vs some

approximately is not an adjective while some is an adjective.

Word	Noun	Adjective	Verb	Adverb
approximately	No	No	No	Yes
some	No	Yes	No	Yes

As adverbs, approximately and some are synonyms defined as:

approximately and some: (of quantities) imprecise but fairly close to correct

Other synonyms of approximately include about, around, close to, just about, more or less, or so, roughly.

approximately (adjective)	some (adjective)
	(quantifier) used with either mass nouns or plural count nouns to indicate an unspecified number or quantity
	remarkable
	relatively many but unspecified in number

approximately (adverb)	some (adverb)
(of quantities) imprecise but fairly close to correct	(of quantities) imprecise but fairly close to correct