The most common and most likely answer to this crossword clue is the 6 letter word TENNIS
I've seen this crossword clue in The Times
T
E
N
N
I
S
More clues leading to the result TENNIS
- Group round bar suffering reversal in game
- Commit fault by net after returning – in this sport?
- Son in difficulty makes comeback in game
- Rallying mid-morning? Not quite
- Slip catch turned game
- It may see some balls in nets returned?
- Nearly all of soccer team is accepting new sport
- Wrong score overturned in game
- Time to go to Irish county town for a game
- Five couples commit offence, returning for court action
Buddy explains!

The straight part
We know that "court action" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case court action = tennis.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 TENNIS mean?
TENNIS noun- A sport played by two players (or four in doubles), who alternately strike the ball over a net using racquets.
- A match in this sport.
- An earlier game in which a ball is driven to and fro, or kept in motion by striking it with a racquet or with the open hand.
- To play tennis.
- To drive backward and forward like a tennis ball.