Cunning men in fitting rooms (9)
I believe the answer is:
apartment
'rooms' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for apartment that I've seen before include "place to live" , "19 across" , "pad" , "Penthouse" , "Flat (mainly US)" .)