The most common and most likely answer to this crossword clue is the 7 letter word FASTENS
I've seen this crossword clue in The Daily Telegraph
F
A
S
T
E
N
S
More clues leading to the result FASTENS
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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 FASTENS mean?
FASTENS verb- To attach or connect in a secure manner.
- To cause to take close effect; to make to tell; to land.