Run down gradient in disarray, heading east (9)
I believe the answer is:
denigrate
'run down' is the definition.
(I've seen this before)
'gradient in disarray heading east' is the wordplay.
'in disarray' indicates anagramming the letters.
'heading east' becomes 'e' (abbreviation).
'gradient' is an anagram of 'denigrat'.
'denigrat'+'e'='DENIGRATE'
(Other definitions for denigrate that I've seen before include "Unfairly criticise" , "Blacken" , "put down" , "Defame" , "Slight" .)