Noun
unsharpness (uncountable)
The condition of being unsharp, usually with reference to imaging (e.g., radiography, computed tomography).
Although it is not always possible to achieve both the desired subject sharpness and the desired background unsharpness, several techniques can be used to increase the separation of subject and background. Source: Internet
Other authors (Adams 1980, 51) have taken the opposite position, maintaining that slight unsharpness in foreground objects is usually more disturbing than slight unsharpness in distant parts of a scene. Source: Internet