Carefully examine including old film as example of literature (6)
I believe the answer is:
poetry
'example of literature' is the definition.
(poetry is a type of literary writing)
'carefully examine including old film' is the wordplay.
'carefully examine' becomes 'pry' (to pry is to examine nosily).
'including' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'film' becomes 'ET' (E.T. the Extra-Terrestrial).
'o'+'et'='oet'
'pry' going around 'oet' is 'POETRY'.
'as' is the link.
(Other definitions for poetry that I've seen before include "Literary genre" , "'Best words in best order' (Coleridge)" , "Metrical writing" , "Work by Keats or Shelley, say" , "Literary art" .)