VIP vs high-up

VIP and high-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
VIP	Yes	No	No	No
high-up	Yes	No	No	No

As nouns, VIP and high-up are synonyms defined as:

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

Other synonyms of VIP include dignitary, high muckamuck, panjandrum, very important person.

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