confraterniser

Confraterniser is a rare, old-fashioned variant of the far more common fraterniser (to fraternize, to bond as if brothers) — most modern French speakers would simply say fraterniser and might not recognize this form at all.

• Les soldats des deux camps ont fini par confraterniser. — Soldiers from both sides ended up fraternizing.
• Il est rare de confraterniser autant avec des inconnus. — It's rare to bond so much with strangers.
• Les délégations ont confraternisé lors du dîner officiel. — The delegations fraternized during the official dinner.

This verb is essentially obsolete outside old texts — a learner using it in everyday speech should reach for fraterniser instead, which means exactly the same thing and is the form virtually everyone actually uses.

Often confused with fraterniser.