vi.

1. 发誓；宣誓
   They refused to swear on a Bible.

   他们拒绝手按《圣经》发誓。

2. 诅咒；骂脏话[（+at）]
   What is the woman swearing at?

   那女人在咒骂什么？

vt.

1. 发（誓）；宣（誓）
   Before giving evidence you have to swear an oath.

   在作证之前你得先发誓。

2. 发誓要；起誓保证[+to-v][+（that）]
   The witness swore to tell the truth.

   证人起誓保证讲真话。

3. 【口】断言；保证说[W][Y][+（that）]
   He swore that he had never talked with the girl.

   他发誓说，他从未与那个姑娘说过话。

4. 使宣誓[（+to）]
   You must swear him to silence.

   你一定要他发誓保持沉默。

5. 使宣誓就任[H][（+in）]
   The new president will be sworn in January.

   新总统将在一月份宣誓就职。

6. 宣誓对（罪行）作证
   He swore treason against his friend.

   他宣誓对他的朋友犯有叛国罪作证。

v.

1. state or promise solemnly or on oath.
   ▸ (swear someone in) admit someone to a position or office by directing them to take a formal oath.
   ▸compel to observe a certain course of action:

   I am sworn to secrecy.
   ▸ (swear to) give an assurance that something is the case.
   ▸ (swear off) informal promise to abstain from.
   ▸ (swear by) informal have or express great confidence in.
   ▸ (swear something out) US Law  obtain the issue of a warrant for arrest by making a charge on oath.
2. use offensive language, especially to express anger.