1. the act of associating or socializing with people in a friendly way, especially across social, military, or national boundaries
Usage: often used in military or political contexts; can carry a neutral or disapproving tone depending on context
2. friendly or intimate relations between members of opposing groups, especially enemy soldiers or occupying forces and local civilians
Usage: often implies relations that are considered inappropriate or disloyal

Examples

• The military issued strict rules against fraternization between officers and enlisted personnel.
• After the war, fraternization between the occupying forces and local residents was initially forbidden.
• The company discouraged fraternization between management and staff to maintain professional boundaries.
• Fraternization with rival gang members could result in serious consequences.
• The diplomat's fraternization with opposition leaders raised eyebrows among her own government.
• Students were warned against fraternization that might compromise academic integrity.
• Historical accounts describe fraternization between enemy soldiers during the Christmas truce of 1914.