The most common and most likely answer to this crossword clue is the 4 plus 6 letter word NAIL POLISH
I've seen this crossword clue in The Times
N
A
I
L
P
O
L
I
S
H
More clues leading to the result NAIL POLISH
- Secure from Warsaw perhaps, a cosmetic item
- Nothing from European country involving a cosmetic
- Secure language for digital application
- His plan in ruins, picking up fresh oil paint that’s handy
- Seize eastern European’s make-up
- Get language absolutely right that’s applied digitally
- Become fluent in a language to get it at your fingertips
- Fix European digital coverage
- . Catch European using cosmetic
- . Grab, finish cosmetic product
Buddy explains!

The straight part
We know that "cosmetic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cosmetic = nail 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.