The most common and most likely answer to this crossword clue is the 5 letter word SPURN
S
P
U
R
N
More clues leading to the result SPURN
- Disdain incentive, finally stubborn
- Refuse encouragement, having taken note
- Reject urge, mean ultimately
- Slight protuberance on tip of nose
- Reject third of yarn twisted on the outside
- Slight change in team in end, one Pole swapped for another
- Reject incentive, and without cover
- Refuse kick up the backside by leader in nappies
- Incentive none initially reject
- Turn down price put on vase
Buddy explains!

The straight part
We know that "Say no to" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case say no to = spurn.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 SPURN mean?
SPURN noun- An act of spurning; a scornful rejection.
- A kick; a blow with the foot.
- Disdainful rejection; contemptuous treatment.
- A body of coal left to sustain an overhanging mass.
- To reject disdainfully; contemn; scorn.
- To reject something by pushing it away with the foot.
- To waste; fail to make the most of (an opportunity)
- To kick or toss up the heels.