The most common and most likely answer to this crossword clue is the 9 letter word CLIENTELE
I've seen this crossword clue in The Guardian
C
L
I
E
N
T
E
L
E
More clues leading to the result CLIENTELE
- Tell niece, working, to see customers
- Tell niece about regular customers
- Chemical engineer defends right to telephone customers
- Such customers need gin supply to build up intelligence
- Customers given two keys allowed man back inside
- Elect representation to enshrine a legal right for customers
- Customers with legal right in court reported magazine
- They patronise beginning of Easter, crossing part of threshold in church
- Clinic ends telecast with “50% reductions for customers”
- Customers may see legal right in court with team cut by half
Buddy explains!

The straight part
We know that "customers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case customers = clientele.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 CLIENTELE mean?
CLIENTELE noun- The body or class of people who frequent an establishment or purchase a service, especially when considered as forming a more-or-less homogeneous group of clients in terms of values or habits.