Lady of fortune (4)
I believe the answer is:
luck
'fortune' is the definition.
(I know that fortune can be written as luck)
'lady' is the wordplay.
I cannot quite understand how this works, but
'lady' could be 'lu' and 'lu' is found within the answer.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for luck that I've seen before include "Good or bad fortune" , "See 1" , "'Fortune, fate (4)'" , "''The devil''s children has the devil's ....'" , "Chance, fate, fortune" .)