Ancient city’s once fantastic empty hotel? (7)
I believe the answer is:
antioch
'ancient city's' is the definition.
(ancient Greek city)
'once fantastic empty hotel?' is the wordplay.
I cannot really see how this works, but
'empty' could be 'o' and 'o' is present in the answer.
'fantastic' could be 'antic' (synonyms) and 'antic' is located in the leftover letters.
'hotel?' could be 'h' (phonetic alphabet: alpha, bravo, charlie etc.) and 'h' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for antioch that I've seen before include "Ancient city now Antakya" , "Ancient Syria capital" , "Early centre of Christianity" , "early Christian centre" , "Southern Turkish city" .)