Steals new decoration (6)
I believe the answer is:
tassel
'decoration' is the definition.
(I know that tassel is a type of adornment)
'steals new' is the wordplay.
'new' is an anagram indicator.
'steals' is an anagram of 'TASSEL'.
(Other definitions for tassel that I've seen before include "Ornamental hanging tuft" , "Hanger-on perhaps" , "Decorative tuft of threads" , "Mortar board attachment" , "Decorative ending to a cord" .)