Error in copy taking turnover (4)
I believe the answer is:
typo
'error' is the definition.
(typographical error)
'in copy taking turnover' is the wordplay.
'in' indicates a hidden word.
'turnover' says the letters should be written in reverse (the letters turn over).
'opyt' can be found hidden inside 'copy taking'.
'opyt' reversed gives 'TYPO'.
(Other definitions for typo that I've seen before include "Small printing error" , "Misprint" , "Finger problem" , "Literal error in printed matter, in short" , "Thanks; good health!" .)