Bother, wrong name on back of certificate (6)
I believe the answer is:
excite
'bother' is the definition.
(I know that bother is a more specific form of excite)
'wrong name on back of certificate' is the wordplay.
'wrong' becomes 'x' (X is used to mark something as incorrect).
'name' becomes 'cite' (cite can mean to name or list).
'on' is a charade indicator (letters next to each other).
'back of' says to take the final letters.
The last letter of 'certificate' is 'e'.
'x'+'cite'='xcite'
'xcite' put after 'e' is 'EXCITE'.
(Other definitions for excite that I've seen before include "Stir emotionally" , "Cause (someone) to feel very enthusiastic" , "Thrill" , "Elicit enthusiasm" , "Rouse feelings, make eager" .)