Wrong sort of knight (6)
I believe the answer is:
errant
I believe this is a double definition.
'wrong' is the first definition.
(I've seen this before)
'sort of knight' is the second definition.
(as in a knight errant)
(Other definitions for errant that I've seen before include "like Don Quixote?" , "Roving" , "so some knights are called" , "Travelling in search of adventure like knight of old" , "heretical?" .)