Showing good judgment in point about discourteous knight (7)
I believe the answer is:
prudent
'showing good judgment' is the definition.
(prudence can mean good judgment)
'point about discourteous knight' is the wordplay.
'point' becomes 'pt' (abbreviation for point).
'about' means one lot of letters goes inside another.
'discourteous' becomes 'rude' (I've seen this before).
'knight' becomes 'N' (chess abbreviation).
'rude'+'n'='ruden'
'pt' going around 'ruden' is 'PRUDENT'.
'in' acts as a link.
(Other definitions for prudent that I've seen before include "caution" , "With care/forethought" , "Careful, circumspect" , "Thinking of the future" , "Acting with care for the future" .)