Horrible to rent out (6)
I believe the answer is:
rotten
'horrible' is the definition.
(thesaurus)
'to rent out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'to'+'rent'='torent'
'torent' with letters rearranged gives 'ROTTEN'.
(Other definitions for rotten that I've seen before include "Putrefied; punk leader" , "Suffering from decay" , "Dedayed, stinking" , "Decaying - quite putrid" , "'Decayed, stinking (6)'" .)