Wear shirt unbuttoned? Journalist material (6,5)
I believe the answer is:
harris tweed
'material' is the definition.
(Harris tweed is an example)
'wear shirt unbuttoned? journalist' is the wordplay.
'unbuttoned?' indicates anagramming the letters (the original order is relaxed or unbuttoned).
'journalist' becomes 'ed' (short for editor).
'wear'+'shirt'='wearshirt'
'wearshirt' anagrammed gives 'harristwe'.
'harristwe'+'ed'='HARRIS TWEED'
(Other definitions for harris tweed that I've seen before include "Woollen cloth from the Outer Hebrides" , "Rough Scots cloth" , "Cloth from Scottish island" , "Scottish material" , "Cloth from Scots island" .)