Blunting means to manipulate a DNA string so that the two strings are full - there won't be any space. The whole procedure will be done by cutting the hanging end at the right and fill the hanging end at the front.
If one of the two singel strings is empty then bluntin fills the empty sting with the complement of the other.

If you have some DNA like in Cut it will lead after "Blunting" to this:

Copy & Cut Help Index Split