The most common and most likely answer to this crossword clue is the 8 letter word STOPPING
I've seen this crossword clue in The Sunday Telegraph
S
T
O
P
P
I
N
G
More clues leading to the result STOPPING
Buddy explains!

The straight part
We know that "Finishing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case finishing = stopping.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 STOPPING mean?
STOPPING verb- To cease moving.
- To not continue.
- To cause (something) to cease moving or progressing.
- To cease; to no longer continue (doing something).
- To cause (something) to come to an end.
- To close or block an opening.
- (often with "up" or "down") To adjust the aperture of a camera lens.
- To stay; to spend a short time; to reside or tarry temporarily.
- To regulate the sounds of (musical strings, etc.) by pressing them against the fingerboard with the finger, or otherwise shortening the vibrating part.
- To punctuate.
- To make fast; to stopper.
- The act of something that stops; a halt.
- Material for filling a cavity.
- A partition or door to direct or prevent a current of air.
- A pad or poultice of dung or other material applied to a horse's hoof to keep it moist.