How would you describe a sharp or harsh taste or odor?

The word "acrid" is used to describe a taste or odor that is strong, sharp, and often unpleasant, often associated with substances like vinegar or smoke. When something is described as acrid, it implies that the sensation is intense and can be irritating to the senses, particularly to the nose and throat. This term is typically applied to tastes and odors that leave a distinctive, sharp sting, making it the most fitting choice in this context.

While the other options contain their own meanings—such as "azure," which refers to a bright blue color, "fastidious," which describes someone who is very attentive to detail, and "fitful," indicating something that occurs irregularly or intermittently—they do not pertain to tastes or odors, thereby making them unsuitable for describing a sharp or harsh experience.