Wiktionary
peacemonger
n. (context pejorative English) someone who opposes war even when it is considered impractical to do so; a strict pacifist
Usage examples of "peacemonger".
There will be found on board the boat not only a Chinese technician, but a cowardly American peacemonger fairly high in government employment.
In final draft his message warned of the tectonic instability of the continent, and suggested steps the Peacemongers could take to learn if the Warlock had lied.