Dissenter suffering from fatigue (9)
I believe the answer is:
tiredness
'fatigue' is the definition.
(I know that fatigue can be written as tiredness)
'dissenter suffering' is the wordplay.
'suffering' indicates anagramming the letters.
'dissenter' is an anagram of 'TIREDNESS'.
'from' is the link.
(Other definitions for tiredness that I've seen before include "Exhaustion" , "Lassitude; residents (anag.)" , "7 (anag)" , "Weary feeling" , "Residents in state of fatigue" .)