Assume to be a hoax? (3,2)
I believe the answer is:
put on
I believe this clue is a double definition.
'assume' is the first definition.
(I know that assume can be written as put on)
'a hoax?' is the second definition.
(I know that dupery can be written as put-on)
'to be' acts as a link.
(Other definitions for put on that I've seen before include "Don clothes or stage play" , "Apply (to a surface) - present (on stage)" , "Don; mount (a play)" , "Increase as with weight" , "Stage -- hoax" .)