Totally dreadful (7)
I believe the answer is:
abysmal
'totally dreadful' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for abysmal that I've seen before include "Deplorable, extremely bad - say ignorance" , "Very bad indeed" , "Extreme and deplorable, perhaps ignorance" , "Extremely bad, appalling" , "Very bad or bottomless" .)