Rod's out to back it, darling (5)
I believe the answer is:
cutie
'darling' is the definition.
(I've seen this in another clue)
'rod's out to back it' is the wordplay.
'rod' becomes 'cue' (I've seen this before).
'out' indicates putting letters inside.
'to back' says the letters should be written backwards.
'it' written backwards gives 'ti'.
'cue' going around 'ti' is 'CUTIE'.
(Other definitions for cutie that I've seen before include "Appealing young lady" , "something pleasing" , "beauty" , "Attractive girl" , "Smart girl" .)