quote from a dictionary

default: [ di'fɔ:lt ]

n. 假设值,默认(值),不履行责任,缺席
v. 默认,不履行义务,缺席,拖欠
[计算机] 缺省

例句与用法:
1. I default on the installment payment.
我没有付分期应付的款。
2. The team lost a game by default.
那个队因没有出席而输掉比赛。
3. The committee will not meet in default of a chairman.
没有主席委员会就不开会。
4. He was acquitted in default of strong evidence of his guilt.
因无确凿证据而判他无罪.
5. A party to the contract defaulted.
订契约的一方未到场.
6. In the default of one player we have to take the little boy as our team member.
因为缺乏一名运动员我们只好叫这个小男孩做我们的队员。

英英解释:
名词default:

1. loss due to not showing up

2. act of failing to meet a financial obligation
同义词：nonpayment, nonremittal

3. loss resulting from failure of a debt to be paid
同义词：nonpayment, nonremittal

4. an option that is selected automatically unless an alternative is specified
同义词：default option

动词default:

1. fail to pay up
同义词：default on