Lady's ruined unfortunately (5)
I believe the answer is:
sadly
'unfortunately' is the definition.
(synonyms)
'lady's ruined' is the wordplay.
'ruined' indicates an anagram.
'ladys' with letters rearranged gives 'SADLY'.
(Other definitions for sadly that I've seen before include "I regret to say" , "With sorrow" , "Alas" , "Regrettably" , "Unhappily" .)