The most common and most likely answer to this crossword clue is the 7 letter word SADDENS
I've seen this crossword clue in The Daily Telegraph
S
A
D
D
E
N
S
Buddy explains!

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 SADDENS mean?
SADDENS verb- To make sad or unhappy.
- To become sad or unhappy.
- To darken a color during dyeing.
- To render heavy or cohesive.