Polish force that is defending point (7)
I believe the answer is:
finesse
'polish' is the definition.
(both can mean impressive flair or style)
'force that is defending point' is the wordplay.
'force' becomes 'F' (symbol used in Physics e.g. f=ma).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'defending' is an insertion indicator.
'point' becomes 'ness' (I've seen this in other clues).
'ie' enclosing 'ness' is 'inesse'.
'f'+'inesse'='FINESSE'
(Other definitions for finesse that I've seen before include "Artifice" , "Clever or crafty manoeuvring" , "Subtlety of contrivance in cards" , "Impressive skill and delicacy" , "Achieve with subtlety and skill" .)