Thanks court for discretion (4)
I believe the answer is:
tact
'discretion' is the definition.
(being tactful is being discreet)
'thanks court' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'court' becomes 'ct' (abbreviation used in road names).
'ta'+'ct'='TACT'
'for' acts as a link.
(Other definitions for tact that I've seen before include "Sensitivity (in dealing with others)" , "Delicacy of feeling, skill in saying the right thing" , "Diplomatic sensitivity" , "measure of diplomacy?" , "Consideration and sensitivity" .)