Hoax, pretence (4)
I believe the answer is:
sham
This clue is a double definition.
'hoax' is the first definition.
(I've seen this in another clue)
'pretence' is the second definition.
(both can mean a facade or fake display)
(Other definitions for sham that I've seen before include "Mash, being false" , "Mock" , "Not what it seems to be" , "False, pretend" , "Counterfeit or insincere" .)