large Mediterranean island (8)
'large mediterranean island' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for crete that I've seen before include "Island whose largest city is Heraklion" , "Greek island, site of the Minoan civilisation" , "Mediterranean island with Minoan remains" , "Large Greek island" , "Large island in Med" .)
(Other definitions for sardinia that I've seen before include "Large Italian island, capital Cagliari" , "Island belonging to Italy" , "Adrian is seen in Mediterranean island" , "Second-largest Mediterranean island, after Sicily" , "Corsican neighbour" .)
(Other definitions for cyprus that I've seen before include "Partitioned Med. island" , "European island country" , "Mediterranean island, capital Nicosia" , "Limassol's island" , "Mediterranean island of Aphrodite" .)