delinquent

adj

1. Late or failing to pay a debt or other financial obligation, like a mortgage or loan.

   “Fred is delinquent in making his car payment.”

2. Of a payment or other financial obligation: late or otherwise unfulfilled.

   “The company made a new effort to collect delinquent payments.”

   “The station's financial difficulties came to a head last week when the Internal Revenue Service had its bank accounts frozen as a result of delinquent taxes.”

3. Failing in or neglectful of a duty or obligation; guilty of a misdeed or offense

noun

1. One who disobeys or breaks rules or laws, or who acts against another's wishes.

   “She had the consolation of knowing that any offence given to her dignity could be avenged on the delinquent who caused it, an act of justice which could not fail to be consolatory, since every one of her daughters had at times stood in stead of "guid King James's whipping-boy," when circumstances arose to disturb the equanimity of Lady Anne's imperious and irascible temper.”

2. A person who has not paid their debts.
3. (derogatory, historical)A royalist in the First English Civil War (1642-1646).