So far Common Era has been an absurd sham! (5)
I believe the answer is:
farce
'absurd sham' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for farce that I've seen before include "Broad comedy" , "Ludicrous comedy" , "Travesty" , "eg 'Noises Off'" , "Forcemeat" .)