Where, anciently, heathens were cut down? (6)
I believe the answer is:
athens
'where anciently' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
'heathens were cut down?' is the wordplay.
'cut down?' indicates the answer is hidden within the clue (some letters cut away to reveal the answer).
'ATHENS' is hidden within 'heathens were'.
Can you help me to learn more?
(Other definitions for athens that I've seen before include "Hasten (anag) -- capital city" , "Hasten to European capital" , "EU capital" , "European capital city" , "foreign city" .)