Tiredness upset nonconformist (9)
I believe the answer is:
dissenter
'nonconformist' is the definition.
(a nonconformist dissents from convention)
'tiredness upset' is the wordplay.
'upset' indicates an anagram.
'tiredness' anagrammed gives 'DISSENTER'.
(Other definitions for dissenter that I've seen before include "One who differs among residents" , "One not agreeing" , "As protester" , "One expressing disagreement" , "One who disagrees among residents" .)