Hint of culture every so often (4)
I believe the answer is:
clue
'hint' is the definition.
(synonyms)
'culture every so often' is the wordplay.
'every so often' means one should take alternating letters.
The alternating letters of 'culture' are 'CLUE'.
'of' acts as a link.
(Other definitions for clue that I've seen before include "Hint to help the puzzler" , "What's this" , "Aid to detection" , "Intimation (like this?)" , "Indication, hint" .)