A short definition of inspiration by Roberto Assagioli:
INSPIRATION AND CREATION
Inspiration and psycho-spiritual creation represent other types of relationship and interaction between the superconscious and consciousness. It is of importance to reach a realization of the differences existing between illumination, inspiration, and creation, and keep them clearly defined, as they are often confused. illumination can confer inspirations and often does so, but not always. With some mystics illumination remains subjective and may create a contemplative state. It often unleashes a rush of love and aspiration to become united with God, to fuse oneself with the Supreme Reality; but it does not necessarily inspire external expression or instigate action.
On the other hand there is the type of inspiration which takes place without illumination, elevation and expansion of consciousness. Most composers experience it at one time or another, but Mozart testified to the frequency with which it virtually “dictated” his works from early childhood on. A distinct difference is to be noted between inspiration and creation. In its deeper sense inspiration denotes the process whereby more or less elaborated contents pass or descend from transpersonal levels, from the superconscious, into the field of consciousness. Creation is, rather, a process whereby these contents are elaborated prior to their descent or appearance in consciousness. Creation is thus analogous to the conception and gestation of a new organism in the maternal uterus, inspiration being analogous to the birth or emergence of the creature.
The “birth” can occur at various stages of the elaboration. In some cases the product enters the consciousness clearly formulated and complete, equipped to pursue an autonomous existence, as occurs biologically in the case of many animals. In others, it “surfaces” in a crude, unfinished state, needing to be worked on, sometimes extensively, by the conscious “I” until it acquires an adequate form. Analogously to physical parturition, the birth is sometimes spontaneous, rapid and easy, and accompanied by a feeling of joy. Yet it can be difficult, protracted and painful. From Transpersonal Inspiration