a person who interferes with, or spoils, a plot or plan
marplot in American English
(ˈmɑrˌplɑt)
noun
a person who mars or spoils some plan by officious interference
term is occasionally applied to things
marplot in American English
(ˈmɑːrˌplɑt)
noun
a person who mars or defeats a plot, design, or project by meddling
Word origin
[1700–10; mar + plot]This word is first recorded in the period 1700–10. Other words that entered Englishat around the same time include: cozy, emphatic, envelope, marquise, sliding scale