Cuckoo or duck in cartoons (5)
I believe the answer is:
daffy
'cuckoo' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for daffy that I've seen before include "Cuckoo" , "Silly, mildly eccentric" , "Bonkers" , "Silly, eccentric (colloq.)" , "Film duck" .)