Old site prepared after for every skill (9)
I believe the answer is:
expertise
'skill' is the definition.
(I have seen 'Technical skill' mean 'expertise' so perhaps 'skill' could also mean 'expertise')
'old site prepared after for every' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'prepared' is an anagram indicator.
'after' means one lot of letters go next to another.
'for every' becomes 'per' ('per' means 'for each' or 'for every').
'site' is an anagram of 'tise'.
'tise' after 'per' is 'pertise'.
'ex'+'pertise'='EXPERTISE'
(Other definitions for expertise that I've seen before include "Special skill or knowledge" , "Thorough knowledge" , "Technical skill" , "Adroitness" , "professionalism" .)