Comedian with cracking sets making a comeback (5-2)
I believe the answer is:
stand up
'comedian' is the definition.
(I know that stand-up is a type of comedian)
'with cracking sets making a comeback' is the wordplay.
'with' becomes 'and'.
'cracking' means one lot of letters goes inside another (inserted letters go into a gap or crack).
'sets' becomes 'puts' ('put' can be a synonym of 'set').
'making a comeback' says the letters should be written in reverse.
'puts' reversed gives 'stup'.
'and' going into 'stup' is 'STAND-UP'.
(Other definitions for stand up that I've seen before include "To wash" , "one has to sit? Not at all" , "Performing solo" , "Fail to keep appointment" , "Performed solo (of a comedy routine)" .)