Natural for tavern to serve tea (6)
I believe the answer is:
innate
'natural' is the definition.
(I know that natural can be written as innate)
'tavern to serve tea' is the wordplay.
'tavern' becomes 'inn' (I've seen this in another clue).
'to serve' indicates an anagram (I've seen 'served' mean this).
'tea' anagrammed gives 'ate'.
'inn'+'ate'='INNATE'
'for' is the link.
(Other definitions for innate that I've seen before include "Born" , "Present from birth" , "Have tea in inn - it's natural" , "Bred in the bone, one might say" , "'Inborn, not learned (6)'" .)