Run down, fed up, James undressed (6)
I believe the answer is:
defame
'run down' is the definition.
(I've seen this before)
'fed up james undressed' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'undressed' says to take the centre (the word removes the letters which clothe it).
The middle letters of 'james' are 'ame'.
'fed' backwards is 'def'.
'def'+'ame'='DEFAME'
(Other definitions for defame that I've seen before include "Injure the reputation of" , "Malign" , "Damage the reputation (of someone)" , "libel" , "Attack someone's good name" .)