vower

oath, pledge, vow

这些名词均含“誓言”之意。
oath: 指对上帝或神发出的庄严、正式的誓言以示自己话语的真实性，现多用于法庭上。
pledge: 普通用词，指保证去做或不做某事的郑重许诺。
vow: 指庄严的许诺或誓约。

名词 vower:

1. someone who makes a solemn promise to do something or behave in a certain way

1. Catholic priests take a vow of celibacy.
   天主教神父发誓不结婚。
2. Once he took the vow his loyalty never wavered.
   他一旦宣了誓，他就一直忠贞不渝。
3. He vowed that he would prosecute them for fraud.
   他郑重宣布将起诉他们犯有欺诈罪。
4. All the men took a vow of loyalty to their leader.
   所有士兵都发誓效忠他们的指挥官。