Wrong, misguided (8)
I believe the answer is:
mistaken
This clue is a double definition.
'wrong' is the first definition.
(similar in meaning)
'misguided' is the second definition.
(synonyms)
(Other definitions for mistaken that I've seen before include "Wrongly understood" , "Wrong, incorrect" , "'Wrong, misguided (8)'" , "In error in mankiest way" , "Wrong (in judgement)" .)