Lose hope, changing diapers (7)
I believe the answer is:
despair
'lose hope' is the definition.
(synonyms)
'changing diapers' is the wordplay.
'changing' indicates an anagram.
'diapers' anagrammed gives 'DESPAIR'.
(Other definitions for despair that I've seen before include "Lose or lack hope" , "Total loss of hope" , "Complete loss of hope" , "The feeling that nothing will turn out well" , "Abandon hope" .)