Fake remake of M*A*S*H (4)
I believe the answer is:
sham
'fake' is the definition.
(sham can mean fake or pretend)
'remake of mash' is the wordplay.
'remake of' indicates anagramming the letters.
'mash' is an anagram of 'SHAM'.
(Other definitions for sham that I've seen before include "Mash, being false" , "False, pretend" , "Pretence; bogus, false" , "Feign" , "Phoney, bogus" .)