Martyr succeeded after that, retaining record (7)
I believe the answer is:
stephen
'martyr' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I don't see?
'succeeded after that retaining record' is the wordplay.
'succeeded' becomes 's' (genealogical abbreviation).
'after' becomes 'then'.
'that retaining' is an insertion indicator.
'record' becomes 'ep'.
'then' enclosing 'ep' is 'tephen'.
's'+'tephen'='STEPHEN'
Can you help me to learn more?
(Other definitions for stephen that I've seen before include "Boy" , "Author of The Shining" , "-- King, US horror writer" , "-- Hawking (A Brief History of Time)" , "Boxing day is St -'s day" .)