What is a defining characteristic of a "neat" drink?

A defining characteristic of a "neat" drink is that it is poured straight from the bottle without any mixers, ice, or additional ingredients. This means that the drink is served at room temperature, preserving the pure, unaltered flavor of the spirit. Neat drinks are typically served in a short glass, allowing the drinker to enjoy the full essence of the liquor. The emphasis is on the quality and taste of the spirit itself, making it a popular choice among connoisseurs who appreciate the nuances of high-quality spirits.

The other options do not accurately represent a neat drink. Serving a drink with ice, for instance, alters its temperature and dilution, which is contrary to the neat serving style. A frozen glass influences the drink's flavor and mouthfeel, while fruit juice would indicate the presence of mixers, again deviating from the neat definition.