Off-target (6)
I believe the answer is:
errant
'off-target' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for errant that I've seen before include "Behaving badly" , "Like many a knight" , "Straying from the right course" , "Off the mark, wandering" , "Travelling in search of adventure like knight of old" .)