high-up vs very important person

high-up and very important person both are nouns.

Word	Noun	Adjective	Verb	Adverb
high-up	Yes	No	No	No
very important person	Yes	No	No	No

As nouns, high-up and very important person are synonyms defined as:

high-up and very important person: an important or influential (and often overbearing) person

Other synonyms of high-up include dignitary, high muckamuck, panjandrum, VIP.

high-up (noun)	very important person (noun)
an important or influential (and often overbearing) person	an important or influential (and often overbearing) person