For royal tennis? (5)
I believe the answer is:
court
This clue might be a double definition.
'for royal' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'tennis?' is the second definition.
(court tennis is a kind of tennis)
Can you help me to learn more?
(Other definitions for court that I've seen before include "Royal entourage" , "Woo - where tennis is played" , "Woo in legal arena" , "Risk incurring (misfortune)" , "The Yard" .)