Unstated assumption
Unstated assumption is a type of propaganda message which forgoes explicitly communicating the propaganda's purpose and instead states ideas derived from it. This technique is used when a propaganda's main idea lacks credibility, and thus when mentioned directly will result in the audience recognizing its fallacy and nullifying the propaganda.
Also, an unstated assumption is an idea prevalent in the study of critical thinking. For example: If a woman says, "I have to go to the park to pick up my kid, he called me and said he was feeling sick." In this simple example, the unstated assumption is that the woman has a son. As I said, this is just a simple example. However, this concept is an important aspect of problem solving in a variety of situations, as vague as that may sound.
A more complicated, and useful, application can be extrapolated from the following example:
A woman walks by a man named John. John then says to himself, "Wow that girl is so beautiful, I want to marry her." Assuming John is 100% serious when he makes the comment, the unstated assumption here regards John's criteria for choosing a wife. The unstated assumption here is that John only cares about what his mate looks like, to the exclusivity off all other traits, such as intelligence and fidelity. By analyzing his comment and recognizing the unstated assumption, we are able to understand John's motivations and worldview just a little bit better. Thus, being able to recognize unstated assumptions can be quite valuable when analyzing someone's personality, trying to form a rebuttal to an argument, etc.