What intent is not
Intent is different from other possible causes of activity (such as instincts and urges, reflexes, desires, aims, or will). The distinction between will and intent may need to be clarified because it is not self-evident. Intent is a pre-thought, pre-language (in other words pre-construct) phenomenon, while will has a cognitive basis, closely related to decisions. Animals and young children do not show much will (they may exhibit the peculiarities of their character, but this is not will). They do not have an overall conscious control of their actions. Intent, on the other hand, is present in all life forms from the start, although it may not be strong and is often muted by more intense determinants. Will can be triggered by intent but also by other factors (e.g. social pressure, rational principles etc.).
The already mentioned Libet's experiments (p.108) provide experimental support for the difference between will and intent. In the case of a voluntary action, such as moving a finger, for example, a pre-verbal and pre-thought energy impulse (intent) fist initiates a neuronal activity. This is called readiness potential (a tension before an action, detected by EEG as a voltage change in a brain region associated with such action). Formulating the impulse (a cognitive process known as decision and normally associated with will) comes later. It is like a driver who first starts the engine, and only after a few moments moves the car. So, in a way, the engine is prepared for the action before the driver decided to move the car (but after s/he had intended to do so). Congruent with Libet's own conclusions, will (decision) has a purpose either to veto or proceed further with the act (see Libet, 2004).
To summarise, the main difference between intent and other phenomena related to action is that the former is not structured (so it can never be precisely formulated) while the latter are. Roughly speaking, will is based on decisions, desires on imagination, and aims on thinking. Of course, these processes are often intertwined. For instance, intent can underlie an aim (that, as a rule, has a convergent role). The aim can provide a form for intent, but intent is still necessary to sustain the act. Other processes in the body and mind can also trigger, modify, contribute or block an intent, but they do not have intent. Such activities are reflexive or conditioned responses. Only the self-soul intends.