just about vs some

just about is not an adjective while some is an adjective.

Word	Noun	Adjective	Verb	Adverb
just about	No	No	No	Yes
some	No	Yes	No	Yes

As adverbs, just about and some are synonyms defined as:

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

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

just about (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

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