Nothing from one bad deed is required (6)
I believe the answer is:
needed
'is required' is the definition.
(synonyms)
'nothing from one bad deed' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'from' indicates named letters should be taken away.
'bad' indicates anagramming the letters.
'one' with 'o' removed is 'ne'.
'deed' is an anagram of 'eded'.
'ne'+'eded'='NEEDED'
(Other definitions for needed that I've seen before include "Missing" , "Lacked something essential" , "Was in want of" , "'Lacked, required (6)'" , "Essential; called for" .)