vi.

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

   他們拒絕手按《聖經》發誓。

2. 詛咒；罵髒話[（+at）]
   What is the woman swearing at?

   那女人在咒罵什麼？

vt.

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

   在作證之前你得先發誓。

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

   證人起誓保證講真話。

3. 【口】斷言；保證說[W][Y][+（that）]
   He swore that he had never talked with the girl.

   他發誓說，他從未與那個姑娘說過話。

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

   你一定要他發誓保持沉默。

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

   新總統將在一月份宣誓就職。

6. 宣誓對（罪行）作證
   He swore treason against his friend.

   他宣誓對他的朋友犯有叛國罪作證。

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.