It's different in Rotherham (5)
I believe the answer is:
other
'it's different' is the definition.
(similar in meaning)
'in rotherham' is the wordplay.
'in' indicates the answer is hidden within the clue.
'OTHER' is hidden in the letters of 'rotherham'.
(Other definitions for other that I've seen before include "Distinct" , "Different; additional" , "else!" , "Different (from those mentioned)" , "Remaining" .)