The most common and most likely answer to this crossword clue is the 6 plus 6 letter word FRENCH POLISH
I've seen this crossword clue in The Sunday Telegraph
F
R
E
N
C
H
P
O
L
I
S
H
More clues leading to the result FRENCH POLISH
- Beaten pro flinches, heavyweight's heading for a shiner?
- Like two Europeans providing gloss?
- 'Shiner' in two languages?
- Europeans finish
- Like Marie Curie‘s treatment
- 20 with a tongue rub
- Sleek coat shows Parisian chic
- Shiner one European’s given to another!
- Gallic charm providing a superior finish
- Two Europeans finish
Buddy explains!
The straight part
We know that "Shiner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shiner = french polish.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.