What word signifies a high level of sophistication?

The word "urbane" is used to describe someone who is notably sophisticated, polished, and refined in manner and style. It often conveys a sense of elegance and smoothness that is characteristic of cultured individuals, particularly in urban settings. People who are described as urbane typically exhibit a high level of social grace and charm, making them adept at navigating complex social situations.

The other options do not convey this level of sophistication. "Torpid" refers to a state of inactivity or sluggishness, which is opposite to the idea of sophistication. "Vigor" denotes physical strength and good health, lacking any implication of elegance or refinement. "Indelible," while it means something that cannot be removed or forgotten, does not relate to any aspect of sophistication or cultured behavior. Thus, "urbane" stands out as the only term that captures the essence of high sophistication.