Fitzgerald finally gave back everything (4)
I believe the answer is:
ella
'fitzgerald' is the definition.
(musician Ella Fitzgerald)
'finally gave back everything' is the wordplay.
'finally' says to take the final letters.
'back' is a reversal indicator.
'everything' becomes 'all' (all things).
The last letter of 'gave' is 'e'.
'all' reversed gives 'lla'.
'e'+'lla'='ELLA'
(Other definitions for ella that I've seen before include "Diminutive of Eleanor" , "Woman" , "- - Fitzgerald (mus.)" , "Miss" , "Great late jazz singer . . . . Fitzgerald" .)