panjandrum
An important, powerful or influential person; muckamuck.
So he died, / and she very imprudently married the Barber: / and there were present / the Picninnies, / and the Joblillies, / and the Garyulies, / and the grand Panjandrum himself, / with the little round button at top;
1755, Samuel Foote, The Grand Panjandrum (a nonsense poem written to test actor Charles Macklin's claim that he could accurately recite any paragraph of text after a single reading),A self-important or pretentious person.
You can never imagine how delighted I was to find that instead of being the correct sort of big panjandrum you were supposed to be, you were really an old rip like papa.
A massive, rocket-propelled, explosive-laden cart designed by the British military during World War II.
historical
The Panjandrum lurched and overturned, the crash dislodging several of the rockets, which flew low over the beach in all directions […].
Where it comes from
Coined as a nonce word in the 18th century by British dramatist Samuel Foote.
Adapted from the Wiktionary entry panjandrum (CC BY-SA 4.0).