Fair-haired one is an old-fashioned term that refers to someone with blonde or light-colored hair. While it is a charming way to describe someone's appearance, there are other synonyms that could also be used. These include platinum-haired, flaxen-haired, golden-haired, and buttery blonde. Other words that could be used to describe someone with light-colored hair include towheaded, sandy, or even just blonde. Ultimately, the choice of which synonym to use will depend on the context and tone of the writing. Nonetheless, all of these options offer a more modern take on describing someone with light-colored hair than the traditional fair-haired one.