verb
BAD : She returned back after half an hour.
GOOD : She returned after half an hour.
BAD : When is he going to return back the money he owes you?
GOOD : When is he going to return the money he owes you?
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Return contains the meaning 'back': 'He had to return to India to look after his mother.' 'He's left a note asking you to return the book he lent you.'