marplot

From mar +‎ plot. In earliest use as a character name in The Busy Body, by Susanna Centlivre.

• (UK) IPA^(key): /ˈmɑːplɒt/

marplot (plural marplots)

1. A meddlesome person whose activity interferes with the plans of others. [from 18th c.]
   • 1920, Peter B. Kyne, The Understanding Heart, Chapter XI

     “The old marplot has discovered the baby,” Monica whispered. “I suppose it cried and woke him up, and now he thinks he's witness to a miracle.”

   • 2012, Michael Burleigh, ‘Keeping the Flame Alive’, Literary Review, 402:

     Unthinking Anglo-Saxons regard him as a Gallic marplot, rather than the great twentieth-century statesman he was – certainly the greatest Frenchman since Napoleon.

• gatecrasher, interloper, peeping tom, persona non grata, encroacher, backseat driver, kibitzer, meddler, nosy parker, intruder, buttinsky, busybody, yenta