Very old cat in north east complex (7)
I believe the answer is:
ancient
'very old' is the definition.
(I've seen this before)
'cat in north east complex' is the wordplay.
'north' becomes 'N' (abbreviation).
'east' becomes 'e' (abbreviation).
'complex' indicates an anagram.
'cat'+'in'+'n'+'e'='catinne'
'catinne' anagrammed gives 'ANCIENT'.
(Other definitions for ancient that I've seen before include "Bygone" , "no longer current" , "Very old or belonging to times past" , "From the distant past" , "Very old, like some civilizations" .)