Which term best describes someone who is highly cultured or intellectual?

The term that best describes someone who is highly cultured or intellectual is "highbrow." This term specifically refers to individuals who have refined tastes, a deep appreciation for the arts, and a strong inclination towards intellectual pursuits. Highbrow denotes a sophistication that is often associated with educated individuals who engage in cultural activities, advanced knowledge, and critical thinking.

In contrast, the other terms do not align with the idea of being highly cultured or intellectual. "Illustrious" refers to someone who is well-known and respected, usually due to notable achievements, but it does not specifically imply a focus on culture or intellect. "Hospitable" describes a person who is welcoming and friendly, particularly toward guests, which is unrelated to cultural or intellectual attributes. Lastly, "idolatry" refers to the worship of idols or excessive admiration for something, which again strays away from the aspects of being cultured or intellectual. Therefore, "highbrow" is the most suitable term for describing an individual with high cultural and intellectual standards.