Nasty story about capturing victor (4)
I believe the answer is:
evil
'nasty' is the definition.
(thesaurus)
'story about capturing victor' is the wordplay.
'story' becomes 'lie' (story can mean a fabrication).
'about' shows that the letters should be reversed in order.
'capturing' is an insertion indicator.
'victor' becomes 'V' (phonetic alphabet: alpha, bravo, charlie etc.).
'lie' in reverse letter order is 'eil'.
'eil' going around 'v' is 'EVIL'.
(Other definitions for evil that I've seen before include "Morally objectionable behavior" , "Immorality" , "Badness, depravity" , "Wicked, sinful" , "Malign" .)