The most common and most likely answer to this crossword clue is the 8 letter word INFAMIES
I've seen this crossword clue in The Guardian
I
N
F
A
M
I
E
S
Buddy explains!
The straight part
We know that "Such deeds must be shocking/Such deeds must be shocking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case such deeds must be shocking/such deeds must be shocking = infamies.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INFAMIES mean?
INFAMIES noun- The state of being infamous.
- A reputation as being evil.
- A reprehensible occurrence or situation.
- A stigma attaching to a person's character that disqualifies them from being a witness.