What is the defining characteristic of a “frozen” cocktail?

A frozen cocktail is distinguished primarily by its texture, which is achieved by blending ice with the other ingredients. This process transforms the drink into a slushy consistency, making it refreshing and perfect for warm weather. The incorporation of ice not only cools the drink but also contributes to its unique mouthfeel, setting it apart from other cocktail styles.

The other choices focus on different aspects of cocktail preparation but do not capture the essence of what makes a cocktail "frozen." For example, serving a cocktail straight without ice is characteristic of neat drinks, while high-proof spirits refer to the alcohol content rather than the texture. Lastly, the use of only fresh fruit pertains to the ingredients rather than the method of preparation or the drink's texture. Thus, blending with ice to achieve a slushy consistency is the defining characteristic of a frozen cocktail.