Force Noel to get involved in depravity (8)
I believe the answer is:
violence
'force' is the definition.
('violence' can be a synonym of 'force')
'noel to get involved in depravity' is the wordplay.
'to get involved' indicates an anagram.
'in' indicates putting letters inside.
'depravity' becomes 'vice' (I've seen this before).
'noel' anagrammed gives 'olen'.
'olen' inserted within 'vice' is 'VIOLENCE'.
(Other definitions for violence that I've seen before include "Aggressive force" , "Unjustifiable force" , "Force, power" , "Aggro" , "Harmful behaviour" .)