At tennis, is it illegal? (6)
I believe the answer is:
racket
This clue might be a double definition.
'at tennis' is the first definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'it illegal?' is the second definition.
The definition suggests a singular noun which matches the answer.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for racket that I've seen before include "Din; snowshoe" , "Unpleasant noise, bat" , "Awful noise" , "Fraudulent scheme" , "Loud unpleasant noise" .)