Enthusiast is more elaborate (7)
I believe the answer is:
fancier
I believe this is a double definition.
'enthusiast' is the first definition.
(I know that enthusiast can be written as fancier)
'more elaborate' is the second definition.
('fancy' can be similar in meaning to 'elaborate')
'is' is the link.
(Other definitions for fancier that I've seen before include "More elaborate - lover (of pigeons, for instance?)" , "one imagines" , "connoisseur" , "This is not so simple" , "More highly decorated" .)