Island oddly curved then (5)
I believe the answer is:
crete
'island' is the definition.
(Greek island)
'oddly curved then' is the wordplay.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
'curved'+'then'='curvedthen'
The alternating letters of 'curvedthen' are 'CRETE'.
(Other definitions for crete that I've seen before include "Large island south of Greece, once home to the Minoans" , "Greek island, capital Heraklion" , "Island whose largest city is Heraklion" , "Mediterranean island with Minoan remains" , "Largest Greek island" .)