Local experimental cinema snubbed over regressive editor (7)
I believe the answer is:
endemic
'local' is the definition.
(I've seen this before)
'experimental cinema snubbed over regressive editor' is the wordplay.
'experimental' is an anagram indicator.
'snubbed' means to remove the last letter (could historically mean cutting the end off).
'over' indicates putting letters inside.
'regressive' says the letters should be written backwards (to regress is to go backwards).
'editor' becomes 'ed' (abbreviation).
'ed' backwards is 'de'.
'cinema' with its last letter taken away is 'cinem'.
'cinem' is an anagram of 'enmic'.
'enmic' placed around 'de' is 'ENDEMIC'.
(Other definitions for endemic that I've seen before include "(Of a disease) prevalent in a group or area" , "Native to a certain area" , "Native to (med.)" , "Rooted in a locality" , "Commonly found in a particular country or people" .)