Every second film has vacuous parts for cheeky youngsters (4)
I believe the answer is:
imps
'cheeky youngsters' is the definition.
'imps' can be an answer for 'youngsters' (imp is a kind of youngster). I am not certain of the 'cheeky' bit.
'every second film has vacuous parts' is the wordplay.
'every second' means one should take alternating letters (I've seen 'every second of' mean this).
'has' is a charade indicator (letters next to each other).
'vacuous' says to hollow out the word (remove centre letters).
'parts' with its centre taken out is 'ps'.
The alternating letters of 'film' are 'im'.
'im'+'ps'='IMPS'
'for' is the link.
Can you help me to learn more?
(Other definitions for imps that I've seen before include "Little monkeys?" , "Small devils or mischievous children" , "Mischievous fairies" , "Mischievous sprites" , "Troublemakers" .)