Deceptive trick or scam (4)
I believe the answer is:
hoax
I believe this clue is a double definition.
'deceptive trick' is the first definition.
(I've seen this before)
'scam' is the second definition.
(I've seen this in another clue)
(Other definitions for hoax that I've seen before include "Spoof" , "Humorous or malicious deception" , "Kid" , "A joking kind of deception" , "Prank" .)