Furious. Is once more back in seed (3,3)
I believe the answer is:
see red
'furious is' is the definition.
I can't judge whether this definition defines the answer.
'once more back in seed' is the wordplay.
'once more' becomes 're' (prefix in words like 're-emerge' or 're-enter').
'back' shows that the letters should be reversed in order.
'in' is an insertion indicator.
're' back-to-front is 'er'.
'er' going into 'seed' is 'SEE RED'.
Can you help me to learn more?
(Other definitions for see red that I've seen before include "Be annoyed" , "Become furious" , "Lose temper like raging bull" , "Lose temper as bull might" , "Become angry as bull might" .)