Popular success is a term that refers to the level of fame and recognition achieved by an individual or group. It can be measured in terms of awards, sales, or other forms of public recognition. In the context of this crossword, the solutions HIT (3 letters) and SMASH (5 letters) refer to the level of success achieved by a person or group. HIT implies a moderate level of success, while SMASH implies a much higher level of success.