Quaintly amusing (5)
I believe the answer is:
droll
'quaintly amusing' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for droll that I've seen before include "Zany" , "Quaintly amusing" , "Whimsically comical" , "amusing, in a strange way" , "Mildly amusing" .)