Lax in sorting out misers (6)
I believe the answer is:
remiss
'lax' is the definition.
(I've seen this before)
'sorting out misers' is the wordplay.
'sorting out' is an anagram indicator.
'misers' anagrammed gives 'REMISS'.
'in' acts as a link.
(Other definitions for remiss that I've seen before include "Negligent, derelict" , "Failing in what duty requires" , "Failing in one's duty" , "Careless concerning a girl?" , "Neglectful" .)