Issue film about military intelligence (4)
I believe the answer is:
emit
'issue' is the definition.
(thesaurus)
'film about military intelligence' is the wordplay.
'film' becomes 'et'.
'about' means one lot of letters goes inside another.
'military intelligence' becomes 'mi' (as in MI5 or MI6 - British military intelligence).
'et' enclosing 'mi' is 'EMIT'.
(Other definitions for emit that I've seen before include "Give out or pour forth" , "Small turtle" , "Give out or put forth" , "Throw out" , "Make audible sounds" .)