Which word would describe an inclination to behave in a certain manner?

The term that describes an inclination to behave in a certain manner is "propensity." This word conveys the idea of a natural tendency or predisposition toward a particular behavior or way of thinking. When someone has a propensity for something, it suggests that they are inclined to engage in that behavior often or easily, emphasizing the habitual aspect of such inclinations.

In contrast, "pungent" refers to a strong smell or taste, often an unpleasant one, and is not related to behaviors. "Renege" means to go back on a promise or commitment, which is not about a general inclination but rather about actions that involve breaking an agreement. "Propriety" relates to conforming to accepted standards of behavior or morality but does not imply a tendency or inclination, rather it describes appropriate behavior in given circumstances. Thus, "propensity" is the most suitable choice for identifying an inclination to behave in a certain manner.