The phrase "team colors" refers to the official colors that represent a particular sports team or organization. When someone is said to be showing their "team colors," it means they are displaying their support for the team by wearing clothing, accessories or other items in those specific colors. This can include jerseys, hats, t-shirts, flags and banners among others. The phrase often used in a positive context to indicate that someone is proudly showing off their loyalty and support for the team they cheer for.