What adjective describes someone who is rich or wealthy?

The adjective that describes someone who is rich or wealthy is "affluent." This term specifically refers to having an abundance of money, goods, or property, indicating a high level of financial stability or wealth. In contexts where financial status is discussed, "affluent" clearly conveys that a person possesses substantial resources.

In contrast, "reticent" refers to someone who is reserved or reluctant to speak, which does not relate to wealth. "Ostentatious" describes actions or behaviors meant to attract attention or admiration, often through excessive display, but it does not directly indicate wealth in a neutral sense—it implies a showy outward display of one’s wealth rather than merely having it. "Impel" means to drive or urge forward, which also bears no connection to wealth or richness. Thus, "affluent" is the correct choice for describing someone who is wealthy.