Remote island is tantalising to some extent (7)
I believe the answer is:
distant
'remote' is the definition.
(I know that remote can be written as distant)
'island is tantalising to some extent' is the wordplay.
'to some extent' says the answer is hidden in the clue.
'DISTANT' can be found hidden inside 'island is tantalising'.
(Other definitions for distant that I've seen before include "Remote in time or place" , "Aloof" , "overseas?" , "Unfriendly; far off" , "Far away" .)