Terrible to rent out (6)
I believe the answer is:
rotten
'terrible' is the definition.
(I've seen this in another clue)
'to rent out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'to'+'rent'='torent'
'torent' anagrammed gives 'ROTTEN'.
(Other definitions for rotten that I've seen before include "Corrupt; very bad" , "Decayed or despicable" , "Morally despicable" , "Suffering from decay" , "Decaying - quite putrid" .)