Misers upset by the delinquent (6)
I believe the answer is:
remiss
'the delinquent' is the definition.
(I've seen this before)
'misers upset' is the wordplay.
'upset' indicates anagramming the letters.
'misers' anagrammed gives 'REMISS'.
'by' is the link.
(Other definitions for remiss that I've seen before include "Negligent in performing duties" , "Negligent, lax" , "Negligent like misers" , "Wrong" , "Negligent, slack" .)