The most common and most likely answer to this crossword clue is the 9 letter word NEWMARKET
I've seen this crossword clue in The Daily Telegraph
N
E
W
M
A
R
K
E
T
More clues leading to the result NEWMARKET
- From the beginning of the season offer game course
- Card game of course?
- Demand for product on ground-breaking course
- Game in horse-racing centre
- Track emerging trade opportunity
- Amphibian all but stressed within 6
- Current commercial opportunity meetings held here
- Course correction for watermen conveying king
- Course that’s what expanding company seeks
- It’s a card game, of course
Buddy explains!

The straight part
We know that "It’s a card game" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s a card game = newmarket.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.