Wryly amusing (6)
I believe the answer is:
ironic
'wryly amusing' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ironic that I've seen before include "Double-edged" , "Wry, sardonic" , "Sarcastic or deliberately perverse" , "Wryly satirical" , "Humorously sarcastic or mocking" .)