Courteousness from old man initially in Leeds, say (6)
I believe the answer is:
comity
'courteousness' is the definition.
(consideration or courteousness towards others)
'old man initially in leeds say' is the wordplay.
'initially' suggests taking the first letters.
'in' means one lot of letters goes inside another.
'leeds say' becomes 'city' (Leeds is a city).
The initial letters of 'old man' is 'om'.
'om' going within 'city' is 'COMITY'.
'from' acts as a link.
(Other definitions for comity that I've seen before include "Courteousness" , "Politeness" , "Civilised state of affairs" , "Civility" .)