past due; not paid at the scheduled time
overdue bill(note)过期(未付)票据
overdue fine 滞纳金；过期罚金
例1：
Appeals or other documents that have been mailed before the expiration of the time period shall not be regarded as overdue.
上诉状或者其他文件在期满前已经交邮的，不算过期。
例2：
Where an employer fails to pay social insurance premiums without proper reason, the labour authority shall order it to pay outstanding premiums within a prescribed time limit; if it fails to make payment within the prescribed time limit, an overdue fine may be imposed on it.
用人单位无故不缴纳社会保险费的，由劳动行政部门责令其限期缴纳；逾期不缴的，可以加收滞纳金。
例3：
Where the borrower fails to repay the loan within the agreed time limit, it shall pay overdue interest in accordance with the terms of the contract or the relevant provisions of the State.
借款人未按照约定的期限返还借款的，应当按照约定或者国家有关规定支付逾期利息。
