Working mere day without a cure (6)
I believe the answer is:
remedy
'cure' is the definition.
(I know that cure can be written as remedy)
'working mere day without a' is the wordplay.
'working' indicates anagramming the letters.
'without' indicates named letters should be taken away.
'day' with 'a' taken out is 'dy'.
'mere' is an anagram of 'reme'.
'reme'+'dy'='REMEDY'
(Other definitions for remedy that I've seen before include "'Cure, medicine (6)'" , "Restorative" , "Cure for disease or difficulty" , "Medicine, treatment" , "Medication" .)