Lessen detail and/or edge definition in an object.

Blurring mimics the limits of our depth perception. Blurred objects appear far away or separated from the viewer by a translucent plane. The fuzziness of a blurred image evokes the haze of being drunk or dizzy.

The Fuzzy Clock. Tibor Kalman (M&Co), 1984

The implications of blurring are generally negative (unfocused, unclear, receding, lessened, obfuscated, abstracted), though blurring one object can bring heightened focus to another, as in this book cover from Mucca:

Book cover design, Mao by Philip Short. Mucca Design, 2007