slang An especially important, influential, and authoritative person, especially someone who is overbearingly or arrogantly so. Sometimes hyphenated. We're just waiting for the muckety mucks in upper management to give us the green light before we get the project started. "All hail the muckety-muck," Jerry muttered under his breath as the CEO walked by.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.