high muck-a-muck

high muckamuck

slang An especially important, influential, and authoritative person, especially someone who is overbearingly or arrogantly so. (Sometimes shortened to simply "muckamuck.") "All hail the high muckamuck," Jerry muttered under his breath as the dictator's motorcade rolled by. We're just waiting for the high muckamuck to give us the green light before we get the project started.
See also: high, muckamuck
Farlex Dictionary of Idioms.

(lord) high muck-a-muck

Rur. a very important person. (Humorous.) Jim's acting like he's some kind of lord high muck-a-muck. What's gotten into him? Mary got a promotion, so now she's a real high muck-a-muck.
See also: high
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • high muckamuck
  • muckamuck
  • muckety
  • high muckety muck
  • high mucky-muck
  • muckety muck
  • odds and ends
  • old enough to be (one's) mother
  • old enough to be mother
  • jockstrapper