Bad alternative to rent (6)
I believe the answer is:
rotten
'bad' is the definition.
(similar in meaning)
'alternative to rent' is the wordplay.
'alternative' indicates anagramming the letters (an alternative ordering of the letters).
'to'+'rent'='torent'
'torent' is an anagram of 'ROTTEN'.
(Other definitions for rotten that I've seen before include "Nasty" , "Decayed or corrupt (60" , "Decayed or despicable" , "Decomposed" , "Putrefied; punk leader" .)