What adjective best describes someone who is artful, cunning, or sly?

The adjective "wily" accurately describes someone who is artful, cunning, or sly, as it conveys a sense of cleverness and the ability to outsmart others, often through the use of deception or trickery. Individuals characterized as "wily" are skilled in navigating complex situations and may use their intelligence to achieve their goals, sometimes employing less than straightforward methods. This term captures the essence of being both resourceful and shrewd, making it an appropriate choice for someone exhibiting these traits.

In contrast, the other options do not fit the description of cunning or slyness. "Naive" suggests a lack of experience or sophistication, making it the opposite of shrewdness. "Sincere" indicates honesty and straightforwardness, which is at odds with the notion of being deceitful or cunning. "Honest" also points to truthfulness and integrity, qualities that are contrary to the artfulness suggested in the question. Thus, "wily" stands out as the term that best encapsulates the desired traits of cunning and craftiness.