Skill of old wife employed in section of media (7)
I believe the answer is:
prowess
'skill' is the definition.
(I've seen this before)
'old wife employed in section of media' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'wife' becomes 'w'.
'employed in' means one lot of letters goes inside another.
'section of media' becomes 'press'.
'o'+'w'='ow'
'ow' going into 'press' is 'PROWESS'.
'of' acts as a link.
(Other definitions for prowess that I've seen before include "Accomplishment" , "Great ability or daring" , "'Skill, expertise (7)'" , "Outstanding skill" , "Acquired skill(s)" .)