Which term describes an office that involves minimal duties?

The term "sinecure" is used to describe a position or office that requires little or no effort from the person who holds it, often providing financial benefits or prestige without demanding substantial responsibilities. This aligns perfectly with the idea of an office that involves minimal duties, as it typically refers to jobs that provide a salary, yet the holder may not have to engage in significant work.

In contrast, the other terms offer different meanings. "Part-time" refers to a job that requires fewer hours than a full-time position, implying some level of responsibility. "Nominal" describes something that is insignificant or minimal in a quantitative sense but does not specifically relate to job responsibilities. Lastly, "casual" describes a type of engagement that is relaxed or informal, but it does not concretely convey the idea of minimal duties in the context of a formal position. Thus, "sinecure" is the most accurate choice for describing an office with minimal duties.