close to vs just about

close to and just about both are adverbs.

Word	Noun	Adjective	Verb	Adverb
close to	No	No	No	Yes
just about	No	No	No	Yes

As adverbs, close to and just about are synonyms defined as:

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

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

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