Make fun of playfully (5)
I believe the answer is:
tease
'make fun of playfully' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tease that I've seen before include "Playfully make fun of" , "Banter, provoke gently" , "Playfully provoke" , "Comb to remove tangles and open out the fibres" , "Make fun of; comb wool" .)