The most common and most likely answer to this crossword clue is the 6 letter word DATIVE
I've seen this crossword clue in The Times
D
A
T
I
V
E
More clues leading to the result DATIVE
- Appointment involves carrying one very small case
- A case of Garland’s last musical making a comeback
- District attorney initially thinks I have a case
- A case of meeting about 4
- Appointment? Four written in in case
- Musical director withdraws case
- I have ordered dates for starters as it relaxes me
- Case providing idea TV exploited
- Fruit boxes drip in this case
- District Attorney: I vet awkward case
Buddy explains!

The straight part
We know that "case" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case case = dative.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 DATIVE mean?
DATIVE noun- (grammar) The dative case.
- (grammar) Noting the case of a noun which expresses the remoter or indirect object, generally indicated in English by to or for with the objective.
- In one’s gift; capable of being disposed of at will and pleasure, as an office or other privilege.
- Removable, as distinguished from perpetual; — said of an officer.
- Given by a judge, as distinguished from being cast upon a party by the law itself.
- Formed by two electrons contributed by one atom; see dative bond.