countermand
/ˌkaʊntəˈmɑːnd/verb
with obj.
1- revoke (an order)撤销; 取消（命令）：
an order to arrest the strike leaders had been countermanded.
逮捕罢工领导人的命令被取消了。
1.1
- cancel an order for (goods)取消购买; 撤销…的订单：
she decided she had been extravagant and countermanded the cream.
她觉得自己太奢侈了, 便取消购买面霜。
1.2
- revoke an order issued by (another person)撤销（别人）的命令：
he was already countermanding her.
他已经在撤销她的命令了。
1.3
- declare (voting) invalid宣布（选举）无效：
the election commission has countermanded voting on the grounds of intimidation.
因为存在恐吓行为, 选举委员会宣布选举无效。
词源
late Middle English: from Old French contremander (verb), contremand (noun), from medieval Latin contramandare, from contra- 'against' + mandare 'to order'.