Brisk is one of those delightful words that sounds like what it means: quick, lively, bracing, and refreshing. There's nothing like a brisk walk in the morning to get the blood flowing and the spirit ready for the day.
Anything brisk is happening quickly but not too fast. Probably taken from the French brusque, which also means "quick," but in a more negative way, brisk can be used to describe not only physical actions but also more conceptual notions, such as brisk business around the holidays or brisk interactions at a speed-dating event. The soft-drink called Brisk must be called that for a good reason. Perhaps it picks you up!