Rascally (7)
I believe the answer is:
roguish
'rascally' is the definition.
(I know that rascally can be written as roguish)
This is all the clue.
(Other definitions for roguish that I've seen before include "Mischievous; unprincipled" , "I gush or change to be waggish" , "Dishonest - mischievous" , "Playfully mischievous" , "reprobate" .)