They call out at court (8)
I believe the answer is:
linesmen
'they' is the definition.
Both the definition and answer are plural nouns.
Maybe you can see an association between them that I don't see?
'call out at court' is the wordplay.
I cannot really see how this works, but
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for linesmen that I've seen before include "Sports officials - those who maintain cables" , "Telephone company employees" , "Assistant referees" , "Football officials" , "Officials who assist referee from the side" .)