By name, a lord (5)
I believe the answer is:
byron
'a lord' is the definition.
(I have seen 'Poetic lord ' mean 'byron' so perhaps 'lord' could also mean 'byron')
'by name' is the wordplay.
'name' becomes 'ron' (short for Ronald).
'by'+'ron'='BYRON'
(Other definitions for byron that I've seen before include "Romantic poet, helped Greeks" , "Lord George, poet" , "Lord . . . . ., English poet who wrote 'Childe Harold's Pilgrimage'" , "Author of 'Don Juan'" , "Eng. romantic poet (Don Juan)" .)