The lady’s circle has a man of courage (4)
I believe the answer is:
hero
'a man of courage' is the definition.
(thesaurus)
'the lady's circle' is the wordplay.
'the lady' becomes 'her' (her refers to a woman).
'circle' becomes 'O' (O is a circle).
'her'+'o'='HERO'
'has' is the link.
(Other definitions for hero that I've seen before include "Very brave man" , "Exceptionally courageous person" , "Admired champion" , "One looked up" , "Person distinguished by exceptional courage" .)