dignitary vs high-up

dignitary and high-up both are nouns.

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

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

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

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

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