Definition of unsharp in English:
 unsharp
adjectiveʌnˈʃɑːpˌənˈSHärp
1Not sharp; dull or blunt.
 a very soft and unsharp brown pencil
2Photography 
(of a picture or image) not well defined.
 Example sentencesExamples
-  See my image editing article for more information on sharpening and unsharp mask.
 -  Here is a tip for sharpening with the unsharp mask filter.
 -  One handed shooting is lazy and you will always run the risk of unsharp shots!
 -  You may notice that the entire image has the unsharp mask applied to it beforehand.
 -  The book is printed in hardcover with an attractive layout and cover, but the illustrations are terribly muddy and unsharp.