Be abusive about the simply shocking (6)
I believe the answer is:
revile
'be abusive' is the definition.
I can't tell whether this definition defines the answer.
'about the simply shocking' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'the simply shocking' becomes 'vile' (I can't explain this - if you can you should believe this answer much more).
're'+'vile'='REVILE'
Can you help me to learn more?
(Other definitions for revile that I've seen before include "Abusively criticise" , "Upbraid or abuse" , "Run down" , "Vilify" , "Criticise in abusive language" .)