Places frequently visited — by ghosts? (6)
I believe the answer is:
haunts
'ghosts?' is the definition.
('haunt' can be a synonym of 'ghost')
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for haunts that I've seen before include "Visits like a ghost" , "Frequently visits" , "Frequents or visits as a ghost" , "Places frequented" , "Places where ghosts hang out?" .)