Left with trendy old floor covering (4)
I believe the answer is:
lino
'floor covering' is the definition.
(short for linoleum)
'left with trendy old' is the wordplay.
'left' becomes 'l' (common abbreviation).
'with' means one lot of letters go next to another.
'trendy' becomes 'in' ('in' can mean fashionable).
'old' becomes 'o' (abbreviation).
'l'+'in'+'o'='LINO'
(Other definitions for lino that I've seen before include "Tough floor covering" , "'Floor covering, in short (4)'" , "put this down?" , "Floor covering (abbr)" .)