Tried working, exhausted (5)
I believe the answer is:
tired
'exhausted' is the definition.
(exhausted can mean very tired)
'tried working' is the wordplay.
'working' indicates an anagram.
'tried' anagrammed gives 'TIRED'.
(Other definitions for tired that I've seen before include "Done in" , "knackered" , "Drowsy" , "Physically or mentally weary" , "Ready to drop" .)