blur
n.
The loss of sharpness in a photographic image resulting from motion of the subject or the camera during exposure.
Notes
Blur may be a flaw or a desired effect. Photographers may use blur to suggest motion, especially in a pan shot where the camera tracks a moving subject to show the subject as relatively sharp against a blurred background. Blur is distinguished from poor focus, the latter being a lack of sharpness resulting from the lens' point of greatest clarity being in front of or behind the subject.
