Cover English prunes with cellophane, finally (7)
I believe the answer is:
eclipse
'cover' is the definition.
(thesaurus)
'english prunes with cellophane finally' is the wordplay.
'english' becomes 'e' (abbreviation).
'prunes' becomes 'clips' ('clip' can be a synonym of 'prune').
'with' is a charade indicator (letters next to each other).
'finally' indicates one should take the final letters.
The final letter of 'cellophane' is 'e'.
'e'+'clips'+'e'='ECLIPSE'
(Other definitions for eclipse that I've seen before include "Celestial phenomenon" , "When light's dropped" , "Decline" , "Overshadow, obscure" , "Black out" .)