Which word describes someone strictly attentive to minute details of form in action or conduct?

The term that best captures someone who is strictly attentive to minute details of form in action or conduct is "punctilious." This word often conveys a sense of scrupulous precision or adherence to formal rules and conventions. A punctilious person pays great attention to specifics, whether in social etiquette or procedural matters, ensuring that every detail is attended to properly. This aspect of punctiliousness highlights a focus not only on accuracy but also on the appropriate execution of actions according to established standards.

While the other options share some similarities, they emphasize different aspects. "Meticulous" refers to being very careful and precise, particularly with thoroughness in tasks, but it does not specifically imply strict adherence to form or conventions. "Diligent" highlights a consistent and earnest effort in work or duties, focusing more on perseverance than on attentiveness to minute details. "Exacting" relates to rigorous demands and the requirement for precision but does not specifically denote the concern for propriety or formal conduct that punctiliousness implies. Thus, in the context of strict attention to minute details of form and conduct, punctilious is the most fitting choice.