Capri; so terribly dull (7)
I believe the answer is:
prosaic
'dull' is the definition.
(similar in meaning)
'capri so terribly' is the wordplay.
'terribly' indicates an anagram.
'capri'+'so'='capriso'
'capriso' with letters rearranged gives 'PROSAIC'.
(Other definitions for prosaic that I've seen before include "Mundane" , "uninspired" , "Ordinary - not poetical" , "routine" , "Dull - pedestrian" .)