from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An officious meddler whose interference compromises the success of an undertaking.
from the GNU version of the Collaborative International Dictionary of English
- n. One who, by his officious interference, mars or frustrates a design or plot.
from The Century Dictionary and Cyclopedia
- n. One who by officious interference mars or defeats a design or plot; one who blunderingly hinders the success of any undertaking or project.
After Marplot, a character in The Busy Body, a play by Susannah Centlivre (1669-1723).(American Heritage® Dictionary of the English Language, Fourth Edition)
From mar + plot. In earliest use as a character name in The Busy Body, by Susanna Centlivre. (Wiktionary)