Crime involving random lone assault, say (8)
I believe the answer is:
violence
'assault say' is the definition.
(I know that assault is a type of assault)
'crime involving random lone' is the wordplay.
'crime' becomes 'vice' (vice crime is a kind of crime).
'involving' means one lot of letters goes inside another.
'random' is an anagram indicator.
'lone' with letters rearranged gives 'olen'.
'vice' going around 'olen' is 'VIOLENCE'.
(Other definitions for violence that I've seen before include "The unlawful use of force, brutality" , "Ferocity" , "Acts of aggression" , "Aggro" , "Use of great force or intensity" .)