Which word means having a natural inclination toward something?

The word "propensity" refers to a natural inclination or tendency to behave in a certain way or to have a particular characteristic. When someone has a propensity for something, it suggests that they are predisposed or have an innate inclination toward it, making it a strong representative of the idea of a natural inclination.

In the context of the other choices, while "tendency," "proneness," and "disposition" also convey aspects of inclination, "propensity" specifically highlights that natural, often habitual inclination in a more pronounced manner. "Tendency" may refer to a general direction or regular pattern but can lack the nuance of natural inclination. "Proneness" often has a connotation of vulnerability or susceptibility, which may not capture the same level of innate inclination. "Disposition" typically refers to a person's inherent qualities of mind and character but may not explicitly denote inclination toward an action or behavior as strongly as "propensity" does. Thus, "propensity" stands out as the most accurate term for having a natural inclination toward something.