'Enemies of Trump' in retreat after revolution? Not your concern (5,4)
I believe the answer is:
never mind
'not your concern' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'enemies of trump in retreat after revolution?' is the wordplay.
'enemies of trump' becomes 'vermin' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'retreat' becomes 'den' (both can mean a lair or hideout).
'after revolution?' says the letters should be written in reverse (letters revolve back).
'den' reversed gives 'ned'.
'vermin' going into 'ned' is 'NEVER MIND'.
Can you help me to learn more?
(Other definitions for never mind that I've seen before include "Don't worry" , "It doesn't matter" , "who cares?" , "Forget" .)