The most common and most likely answer to this crossword clue is the 6 letter word NAYSAY
N
A
Y
S
A
Y
Buddy explains!

The straight part
We know that "Refuse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case refuse = naysay.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 NAYSAY mean?
NAYSAY noun- A refusal, denial, or negation.
- To speak negatively of something.
- To reply no.