A person who fraternizes with others, especially across social, national, or group boundaries.
From 'fraternize' plus the agent suffix '-er.' Denotes one who engages in fraternization, often with social or political implications.
After WWI and WWII, being labeled a 'fraternizer' could be serious—in some contexts it meant collaborator, traitor, or someone too sympathetic to the enemy, but in others it meant idealist and peacemaker.
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