What term refers to actions driven by a sudden desire or impulse?

The term that describes actions driven by a sudden desire or impulse is "spontaneous." This term highlights the nature of actions that occur without prior planning or forethought, often in response to immediate urges or feelings. Spontaneous actions can be seen as instinctual or reactive, contrasting with approaches that involve careful consideration or prearranged steps.

In this context, planned, preplanned, and organized specifically refer to actions that involve a level of preparation and strategy. These terms denote a structured approach to decision-making and execution, which stands in stark contrast to the impulsive nature of spontaneity. Therefore, spontaneous is the most fitting choice as it encapsulates the essence of acting on impulse in an unregulated manner.