The most common and most likely answer to this crossword clue is the 9 plus 6 letter word FINISHING SCHOOL
I've seen this crossword clue in The Daily Telegraph
F
I
N
I
S
H
I
N
G
S
C
H
O
O
L
More clues leading to the result FINISHING SCHOOL
- Swimmers after water sport gathering in training place
- Posh girls' establishment disposing of tutor?
- Place to learn Polish — something pupils like?
- Eating up some fish, females here instructed
- Come out? Some who went here may have done so afterwards
- Teaching establishment getting rid of coach
- Training academy swimmers on the last length?
- Perfect gin drunk on train — source of refinement?
- Polish girls here maybe foolishly choosing to be detained by heartless Nordic lecturer
- Searching around in swimming group that trains young ladies
Buddy explains!
The straight part
We know that "Teaching establishment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case teaching establishment = finishing school.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.