Puts back bullock rolling round fields at last (6)
I believe the answer is:
resets
'fields at last' is the definition.
Although both the answer and definition are verbs in their -s form, I don't see how they can define each other.
'puts back bullock rolling round' is the wordplay.
'puts back' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'bullock' becomes 'steer' (synonyms).
'rolling' says the letters should be written backwards.
'round' means one lot of letters goes inside another.
'steer' backwards is 'reets'.
's' inserted within 'reets' is 'RESETS'.
Can you help me to learn more?
(Another definition for resets that I've seen is " Readjusts".)