What it means: Showing your true colours allow you to reveal your true self to someone. Where it comes from: When countries used to fight war at sea, enemies (and pirates) would often fly with the colours and flags of an alliance, making it easier for them to conceal their true identity and nationality, therefore having the advantage in battle. However, this wasn't technically allowed as not only was it immoral, it also went against the rules of warfare. Everyone had to fly with their true colours before firing, but it's war, and anything goes. Men were only thinking about how to survive, not about maintaining etiquette with their enemies.
