Farce - son is game (8)
I believe the answer is:
charades
'is game' is the definition.
(I've seen this before)
'farce son' is the wordplay.
'farce' becomes 'charade' (both can mean absurd or false situation).
'son' becomes 's' (genealogical abbreviation for son).
'charade'+'s'='CHARADES'
(Other definitions for charades that I've seen before include "Games like this" , "Miming parlour game" , "Guessing game where words are acted out" , "Party guessing game" , "Game in which answers are acted out" .)