What is the term for a natural inclination or propensity?

The term that best describes a natural inclination or propensity is "disposition." This word refers to a person's inherent qualities of mind and character, indicating a natural tendency toward a specific behavior or way of thinking. While "tendency" also implies a natural inclination, it typically suggests a more specific or observable behavior in certain situations rather than an overarching characteristic of someone’s nature.

Preference refers to a choice or favoring something over another, which could be influenced by experiences or desires, rather than a natural inclination. Adjustment usually conveys the idea of modifying or adapting to new conditions, so it does not align with the concept of a natural inclination.

Thus, "disposition" encapsulates the idea of a person's natural qualities and inclinations more fully than the other options.