What is the definition of an action that is done without being planned or organized?

The definition of an action that is done without being planned or organized aligns well with the term "impromptu." This word specifically refers to actions or performances that occur without advance notice or preparation. When something is described as impromptu, it captures the essence of spontaneity and the absence of a predetermined plan, indicating a natural and immediate response to a situation.

In contrast, the term "spontaneous" relates closely to the same idea of acting on impulse or instinct without premeditation. While both terms can imply a lack of planning, "impromptu" is more often associated with an action that occurs in the moment, particularly in contexts like speaking or performing without rehearsal.

Intentional actions are characterized by purpose and planning, which is the opposite of being unplanned or unorganized. Similarly, calculated actions imply a level of deliberation and strategic thinking, which again contrasts with the notion of spontaneity. Thus, the correct choice encapsulates the concept of unplanned or unorganized actions most accurately.