What is the Difference Between a Flavored Whiskey and a Liqueur?

I was just speaking to a bartender that wanted to know the difference between flavored whiskey and liqueur. Hopefully, by now, most of us are aware that Southern Comfort (made so famous by Janis Joplin) is a liqueur, not a whiskey. It is “grain neutral spirit, sugar, and a fruit concentrate in which the dominant fruit is apricot.” (Chuck Cowdery) That means it is basically vodka with flavorings. Flavored whiskey, however, is a different animal. By law (TTB regulations), Flavored Whiskey is described this way- -Whisky flavored with natural flavoring materials, with or without the addition of sugar, bottled at not less than 30% alcohol by volume (60 proof) -The name of the predominant flavor shall appear as part of the class and type designation, e.g.,...