Films get lost by vacuous teenagers (6)
I believe the answer is:
shoots
'films' is the definition.
(shoot can mean to film)
'get lost by vacuous teenagers' is the wordplay.
'get lost' becomes 'shoo' (both can be said to tell someone to go away).
'by' means one lot of letters go next to another.
'vacuous' suggests removing the centre.
'teenagers' with its centre taken out is 'ts'.
'shoo'+'ts'='SHOOTS'
(Other definitions for shoots that I've seen before include "Fires a missile" , "photo sessions?" , "New growths or branches" , "Wounds; germinates" , "fires gun" .)