Wrongly arrest rubberneck (6)
I believe the answer is:
starer
'rubberneck' is the definition.
(to 'rubberneck' can mean to stare at something)
'wrongly arrest' is the wordplay.
'wrongly' indicates an anagram (I've seen this in other clues).
'arrest' is an anagram of 'STARER'.
(Other definitions for starer that I've seen before include "One gazing intently" , "keen viewer" , "looker" , "Person gawping" .)