The most common and most likely answer to this crossword clue is the 10 letter word DEFENDANTS
I've seen this crossword clue in The Guardian
D
E
F
E
N
D
A
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T
S
More clues leading to the result DEFENDANTS
Buddy explains!

The straight part
We know that "They go to court" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they go to court = defendants.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 DEFENDANTS mean?
DEFENDANTS noun- In civil proceedings, the party responding to the complaint; one who is sued and called upon to make satisfaction for a wrong complained of by another.
- In criminal proceedings, the accused.