Spirit of a culture (5)
I believe the answer is:
ethos
'spirit of a culture' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ethos that I've seen before include "Underlying culture of a group" , "Characteristic spirit, of a culture say" , "Distinctive spirit - character" , "Distinctive group spirit" , "Those (anag.)" .)