Playful — mischievous (6)
I believe the answer is:
impish
I believe this clue is a double definition.
'playful' is the first definition.
(similar in meaning)
'mischievous' is the second definition.
(I know that mischievous can be written as impish)
(Other definitions for impish that I've seen before include "Mischievous like small fairy" , "Wicked" , "Mischievous like small devil" , "Teasingly mischievous" , "saucy" .)