Intent to do harm, one caught punching guy (6)
I believe the answer is:
malice
'intent to do harm' is the definition.
(desire to harm someone or do them ill)
'one caught punching guy' is the wordplay.
'one' becomes 'i' (Roman numeral).
'caught' becomes 'c' (cricket abbreviation).
'punching' means one lot of letters goes inside another (some letters punch a hole in others).
'guy' becomes 'male' (guy can mean a man).
'i'+'c'='ic'
'ic' inserted into 'male' is 'MALICE'.
(Other definitions for malice that I've seen before include "Spite, venom" , "Bitterness" , "Spitefulness" , "Malevolence, spite" , "Spite or spleen, perhaps aforethought" .)