hierarch vs important person

hierarch and important person both are nouns.

Word	Noun	Adjective	Verb	Adverb
hierarch	Yes	No	No	No
important person	Yes	No	No	No

As nouns, important person is a hypernym of hierarch; that is, important person is a word with a broader meaning than hierarch:

hierarch: a person who holds a high position in a hierarchy
important person: a person whose actions and opinions strongly influence the course of events

Other hypernyms of hierarch include influential person, personage.

hierarch (noun)	important person (noun)
a senior clergyman and dignitary	a person whose actions and opinions strongly influence the course of events
a person who holds a high position in a hierarchy