Definitions of delinquent:

• noun:   a young offender
• adjective:   guilty of a minor misdeed

  Example: "Delinquent minors"

• adjective:   past due; not paid at the scheduled time

  Example: "A delinquent account"

• adjective:   persistently bad

  Example: "School for delinquent boys"

• adjective:   failing in what duty requires

  Example: "Derelict (or delinquent) in his duty"