The most common and most likely answer to this crossword clue is the 7 letter word SHARPEN
S
H
A
R
P
E
N
More clues leading to the result SHARPEN
- On reduced allowance, writer's become more focused
- Improve cutting edge of small instrument in from France
- Increase pitch of instrument in three different ways
- Dog’s tail docked, and indefinite number get into strop
- Make point on small instrument, then two points
- Hone small instrument tip, interminably …
- Make keener and run into form before end of season
- Give edge to launch site's writer
- File kept by writer is on leading scam highlighting ambiguous riches
- Gaining power, allocate new file
Buddy explains!

The straight part
We know that "File" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case file = sharpen.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 SHARPEN mean?
SHARPEN verb- (sometimes figurative) To make sharp.
- To become sharp.