Stun"ning*ly

from The Collaborative International Dictionary of English v.0.48

Stunning \Stun"ning\, a.
   1. Overpowering consciousness; overpowering the senses;
      especially, overpowering the sense of hearing; confounding
      with noise.
      [1913 Webster]

   2. Striking or overpowering with astonishment, especially on
      account of excellence; as, stunning poetry. [Slang] --C.
      Kingsley. -- {Stun"ning*ly}, adv. [Slang]
      [1913 Webster]