Humorous or malicious deception (4)
I believe the answer is:
hoax
'humorous or malicious deception' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for hoax that I've seen before include "Humorous or malicious deception" , "A fraud or deception" , "Scam" , "A plan to deceive" , "Act of deception" .)