The story
Either a variant of muckamuck (the short form of high muckamuck), or a shortening of high muckety-muck. See the entry muckamuck.
First known use, by meaning
- from 20th c. A high muckamuck; a person (especially self-important) in a position of power, authority, or status.
Etymology from Wiktionary, CC BY-SA 4.0.