The most common and most likely answer to this crossword clue is the 6 letter word DENIAL
I've seen this crossword clue in The Guardian
D
E
N
I
A
L
More clues leading to the result DENIAL
- Renunciation of study, learner of highest standard being upset
- Laid back about English knight’s disclaimer
- Rejection of deal about Northern Ireland
- Cut flowers? Two of them, the second after receiving a rejection
- Losing heirloom ultimately for duke, servant gets dismissal
- Rejection of 7 down an abomination
- Refusal to deliver sandwiches at home withdrawn
- Refusal of agreement to keep Irish province
- No telephone boxes – little space
- Sort of dash into Ring dismissal
Buddy explains!

The straight part
We know that "Refusal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case refusal = denial.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 DENIAL mean?
DENIAL noun- The negation in logic.
- A refusal to comply with a request.
- An assertion of untruth.
- Refusal to believe a problem exists
- A defense mechanism involving a refusal to accept the truth of a phenomenon or prospect.