The largest of the Dodecanese islands (6)
I believe the answer is:
rhodes
'the largest of the dodecanese islands' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rhodes that I've seen before include "British imperialist; Greek island" , "She and Rod have a Greek holiday here" , "Island, explorer" , "Hordes go to the Greek island" , "Shored (anag) - Greek island" .)