Lord, say, implicated in falsehood (5)
I believe the answer is:
liege
'lord' is the definition.
(feudal term for a superior)
'say implicated in falsehood' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'implicated in' means one lot of letters goes inside another.
'falsehood' becomes 'lie' (lie is a kind of falsehood).
'eg' placed within 'lie' is 'LIEGE'.
(Other definitions for liege that I've seen before include "Belgian city or ancient superior" , "Belgian city or ancient lord" , "A person holding land under feudalism" , "Feudal vassal from a Belgian city" , "Belgian city or feudal superior" .)