Hip, say, niece damaged restricts golf sharpness (12)
I believe the answer is:
intelligence
'sharpness' is the definition.
'hip say niece damaged restricts golf' is the wordplay.
'hip' becomes 'in' (I've seen this in other clues).
'say' becomes 'tell' ('tell' can be a synonym of 'say'**).
'damaged' indicates an anagram.
'restricts' is an insertion indicator.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'niece' anagrammed gives 'ience'.
'ience' going around 'g' is 'igence'.
'in'+'tell'+'igence'='INTELLIGENCE'
(Other definitions for intelligence that I've seen before include "Covertly gathered information" , "Mind; news" , "Mental brightness" , "Dope" , "Military information" .)