In the last month, go back over the year, maybe, and deplore it (5)
I believe the answer is:
decry
'and deplore it' is the definition.
I can't judge whether this defines the answer.
'in the last month go back over the year' is the wordplay.
'in the last month' becomes 'ced' (I am not sure about this - if you are sure you should believe this answer much more).
'go back' is a reversal indicator.
'over' says the letters should be written in reverse.
'the year' becomes 'yr' (abbreviation).
'ced' in reverse letter order is 'dec'.
'yr' written backwards gives 'ry'.
'dec'+'ry'='DECRY'
'maybe' acts as a link.
Can you help me to learn more?
(Other definitions for decry that I've seen before include "Disapprove of" , "Publicly denounce" , "Speak out against or disparage" , "Disparage, put down" , "Run down" .)