Scarf, new, obtained illegally (6)
I believe the answer is:
stolen
'obtained illegally' is the definition.
(I've seen this in another clue)
'scarf new' is the wordplay.
'scarf' becomes 'stole' (stole is a kind of scarf).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'stole'+'n'='STOLEN'
(Other definitions for stolen that I've seen before include "` `The ... Child' ' (Yeats)" , "Taken without permission or payment" , "Goods that have been taken dishonestly" , "Snatched" , "Robbed" .)