The most common and most likely answer to this crossword clue is the 7 letter word REFUSAL
I've seen this crossword clue in Independent
R
E
F
U
S
A
L
More clues leading to the result REFUSAL
- Failure to cooperate changing FA rules
- Initially find American to be in genuine denial
- Judge stamping down on American gangster’s noncompliance
- No end of stress amid awful earful
- No judge has us over a barrel in the end
- Earl shamefully accepting fellow American’s knock-back
- Non-acceptance of absurd earfuls
- Fellow American needs genuine protection? No
- Spurning failures sadly lacking independence
- Much ado in genuine case? No!
Buddy explains!

The straight part
We know that "knock-back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case knock-back = refusal.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 REFUSAL mean?
REFUSAL noun- The act of refusing.
- Depth or point at which well or borehole drilling cannot continue.