ap·pall·ing
 /əˈpɑːlıŋ/  adj   [more ~; most ~]
  : very bad in a way that causes fear, shock, or disgust
   We drove by an appalling accident on the highway.
   Your behavior has been appalling. [=atrocious, outrageous, terrible]
  ap·pall·ing·ly  adv  
   appallingly bad treatment
   an appallingly [=dreadfully] bad movie