A hero, but to many a libertine (5)
I believe the answer is:
drake
'a hero' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'to many a libertine' is the wordplay.
'to many' becomes 'd' (Roman numeral for 500).
'a libertine' becomes 'rake' (rake is a kind of libertine).
'd'+'rake'='DRAKE'
'but' is the link.
Can you help me to learn more?
(Other definitions for drake that I've seen before include "Male water-bird" , "Male duck - circumnavigator" , "Plymouth bowler" , "Elizabethan circumnavigator" , "flyer" .)