“White” spirits are clear, generally devoid of color, because they have usually not been aged in color-inducing wooden barrels. Sure, some of them are aged in barrels and then filtered so they look clear (like one very famous rum brand).

The primary difference between clear and dark liquor is their overall level of purity. While all alcohol contains impurities known as congeners, dark liquors tend to contain a higher concentration of them than clear alcohols (via Medical Daily).

Whiskey and brandy are the most common brown liquors. Scotch, a variety of whiskey, and cognac, a type of brandy, fall into this category as well. Brown liquors get their color from barrel aging, sometimes in charred barrels.

Using this logic, a reasonable and objective definition of Light Spirits, consistent with the applicable legislation / regulations is: distilled alcoholic drinks with an ABV of at least 15% and not more than 26.25%.