The story
- Latin · derived from-us“nominative suffix”
- English todayrumpus
Unknown. First use appears c. 1745. The OED indicates: "perhaps an arbitrary formation". Possibly an alteration of rumbustical or rumbustious (“boisterous, noisy”) + Latin -us (“nominative suffix”). The use of the verbal form first appears c. 1839.
Etymology from Wiktionary, CC BY-SA 4.0.