The most common and most likely answer to this crossword clue is the 7 letter word ADJUNCT
I've seen this crossword clue in The Guardian
A
D
J
U
N
C
T
More clues leading to the result ADJUNCT
- Accessory with evening dress: one must get into function
- Supplementary day with month taken in a court
- Auxiliary judge's start in a dingy court
- Extra cool teenager starts following John Peel? Nice one!
- Accessory for a formal suit with new cut around top of neck
- A record spinner with a French court auxiliary
- 10 has a record-player: posh, new and about time
- Rider volunteers to leave military administrator outside entrance to courtyard
Buddy explains!

The straight part
We know that "Accessory" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case accessory = adjunct.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 ADJUNCT mean?
ADJUNCT noun- An appendage; something attached to something else in a subordinate capacity.
- A person associated with another, usually in a subordinate position; a colleague.
- An unmalted grain or grain product that supplements the main mash ingredient.
- A quality or property of the body or mind, whether natural or acquired, such as colour in the body or judgement in the mind.
- A key or scale closely related to another as principal; a relative or attendant key.
- (grammar) A dispensable phrase in a clause or sentence that amplifies its meaning, such as "for a while" in "I typed for a while".
- (X-bar theory) A constituent which is both the daughter and the sister of an X-bar.
- Symploce.
- One of a pair of morphisms which relate to each other through a pair of adjoint functors.
- Connected in a subordinate function.
- Added to a faculty or staff in a secondary position.