Advocate to open next resort (8)
I believe the answer is:
exponent
'advocate' is the definition.
(I know that advocate can be written as exponent)
'open next resort' is the wordplay.
'resort' indicates an anagram (re-sort the letters).
'open'+'next'='opennext'
'opennext' is an anagram of 'EXPONENT'.
'to' is the link.
(Other definitions for exponent that I've seen before include "Interpretive artist or performer" , "Promoter (of an idea or theory)" , "index" , "Interpretive artist - open next (anag)" , "skilful practitioner" .)