marplot

noun

1. Synonym of spoilsport, one who ruins other's plans or enjoyment of something.

   ““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.””

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

adj

1. (archaic)Ruining a plan, interfering, spoilsport.

   “Let us argue the point with this pert, unruly, marplot conscience of mine…”