Carpet to cover floor (5,4)
I believe the answer is:
dress down
'carpet' is the definition.
(I've seen this before)
'cover floor' is the wordplay.
'cover' becomes 'dress' (synonyms).
'floor' becomes 'down' (both can mean to knock to the ground).
'dress'+'down'='DRESS DOWN'
'to' is the link.
(Other definitions for dress down that I've seen before include "Severely reprimand; be informal" , "Severely criticise" , "Sends word to give scolding to" , "Put on casual clothes" , "what office workers do on Fridays?" .)