delinquency vs nonpayment

delinquency and nonpayment both are nouns.

Word	Noun	Adjective	Verb	Adverb
delinquency	Yes	No	No	No
nonpayment	Yes	No	No	No

As nouns, nonpayment is a hypernym of delinquency; that is, nonpayment is a word with a broader meaning than delinquency:

Other hypernyms of delinquency include default, nonremittal.

delinquency (noun)	nonpayment (noun)
an antisocial misdeed in violation of the law by a minor	the deliberate act of failing to pay money
a tendency to be negligent and uncaring	loss resulting from failure of a debt to be paid
nonpayment of a debt when due	act of failing to meet a financial obligation