Royal maids, possibly (5)
I believe the answer is:
midas
'royal' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see an association between them that I don't see?
'maids possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'maids' is an anagram of 'MIDAS'.
Can you help me to learn more?
(Other definitions for midas that I've seen before include "Legendary king with golden touch" , "His touch made gold" , "I'm sad (anag) -- king of Phrygia" , "Everything he touched turned to gold" , "Golden-touch king" .)