Applaud role reversal? That’s rubbish (8)
I believe the answer is:
claptrap
'rubbish' is the definition.
(thesaurus)
'applaud role reversal?' is the wordplay.
'applaud' becomes 'clap' ('clap' can be a synonym of 'applaud').
'role' becomes 'part' ('part' can be a synonym of 'role').
'reversal?' says the letters should be written in reverse (I've seen 'reversal' mean this).
'part' reversed gives 'trap'.
'clap'+'trap'='CLAPTRAP'
'that's' is the link.
(Other definitions for claptrap that I've seen before include "Meaningless, insincere or pompous talk" , "Pretentious talk used to win applause" , "Contrived but foolish talk" , "Balderdash" , "Absurd or nonsensical talk or ideas" .)