1. destructive to both sides in a conflict; mutually destructive
Usage: formal
2. relating to conflict within a group or organization
Usage: formal

Examples

• The internecine war left both nations economically devastated.
• Internecine fighting within the political party weakened their chances in the election.
• The company’s internecine struggles between departments hurt productivity.
• Years of internecine conflict had torn the family apart.
• The internecine nature of the dispute meant there would be no real winners.
• Internecine rivalries among the rebel factions undermined their cause.