Island craft backed by whole area (7)
I believe the answer is:
sumatra
'island' is the definition.
(Sumatra is an example)
'craft backed by whole area' is the wordplay.
'craft' becomes 'art' (I've seen this before).
'backed' shows that the letters should be reversed in order.
'by' is a charade indicator (letters next to each other).
'whole' becomes 'sum' (sum is a kind of whole**).
'area' becomes 'a' (maths abbreviation).
'art' written backwards gives 'tra'.
'sum'+'a'='suma'
'tra' put after 'suma' is 'SUMATRA'.
(Other definitions for sumatra that I've seen before include "Some land" , "part of Indonesia" , "Eastern island" , "Second largest Indonesian island" , "A US mart on an Indonesian island?" .)