provoking horror
"an atrocious automobile accident"
"a frightful crime of decapitation"
"an alarming, even horrifying, picture"
"war is beyond all words horrible"
"an ugly wound"
extreme in degree or extent or amount or impact
"in a frightful hurry"
"spent a frightful amount of money"
Full of fright, whether
Afraid, frightened.
Frightfully; very.