Left excellent, decorative fabric (4)
I believe the answer is:
lace
'decorative fabric' is the definition.
'left excellent' is the wordplay.
'left' becomes 'l' (common abbreviation).
'excellent' becomes 'ace' (I've seen this before).
'l'+'ace'='LACE'
(Other definitions for lace that I've seen before include "Fabric made in openwork design" , "Fortify with spirits; open fabric" , "Shoe cord" , "A fabric; add alcohol to" , "Fine needlework" .)