A delinquent account is any credit agreement that isn't paid by the predetermined due date, according to About.com. Creditors apply monthly late fees to delinquent accounts, but in many cases, consumers are granted grace periods before penalties go into effect.
MSN Money explains that any late payment may be considered "delinquent," but most creditors rank the severity of delinquency in 30-day increments. If the account is unpaid for extensive periods, such as 90 or 120 days, the consumer may receive a significant decrease in credit scoring. The creditor may also issue a charge-off and attempt to collect the entire debt.