Tell untruths for example about feudal lord (5)
I believe the answer is:
liege
'feudal lord' is the definition.
(I've seen this before)
'tell untruths for example about' is the wordplay.
'tell untruths' becomes 'lie' (I've seen this before).
'for example' becomes 'eg' ('e.g.' can be a synonym of 'for example').
'about' shows that the letters should be reversed in order.
'eg' written backwards gives 'ge'.
'lie'+'ge'='LIEGE'
(Other definitions for liege that I've seen before include "City in eastern Belgium" , "European city" , "Loyal vassal" , "Sort of lord" , "Belgian province" .)