Sailor with extremely elegant coat (6)
I believe the answer is:
jacket
'coat' is the definition.
(jacket is a kind of coat)
'sailor with extremely elegant' is the wordplay.
'sailor' becomes 'jack' (I've seen this before**).
'with' says to put letters next to each other.
'extremely' suggests removing the centre.
'elegant' with its centre taken out is 'et'.
'jack'+'et'='JACKET'
(Other definitions for jacket that I've seen before include "in which King Edward got very hot" , "Record sleeve" , "Book cover" , "Short coat or outer skin" , "Blazer" .)