Decoration I bar in a way (6)
I believe the answer is:
riband
'decoration' is the definition.
(thesaurus)
'i bar in a way' is the wordplay.
'bar' becomes 'ban' (bar can mean to ban or prohibit).
'in' is an insertion indicator.
'a way' becomes 'rd' (short for road).
'i'+'ban'='iban'
'iban' placed into 'rd' is 'RIBAND'.
(Other definitions for riband that I've seen before include "Strip of material" , "strip of fabric" , "Four across - is trophy for fastest Atlantic sea crossing" , "decorative strip" .)