Noah Webster's New International Dictionary of the English Language

1. (v. i.) To affirm or utter a solemn declaration, with an appeal to God for the truth of what is affirmed; to make a promise, threat, or resolve on oath; also, to affirm solemnly by some sacred object, or one regarded as sacred, as the Bible, the Koran, etc.

2. (v. i.) To give evidence on oath; as, to swear to the truth of a statement; he swore against the prisoner.

3. (v. i.) To make an appeal to God in an irreverent manner; to use the name of God or sacred things profanely; to call upon God in imprecation; to curse.

4. (v. t.) To utter or affirm with a solemn appeal to God for the truth of the declaration; to make (a promise, threat, or resolve) under oath.

5. (v. t.) To put to an oath; to cause to take an oath; to administer an oath to; -- often followed by in or into; as, to swear witnesses; to swear a jury; to swear in an officer; he was sworn into office.

6. (v. t.) To declare or charge upon oath; as, he swore treason against his friend.

7. (v. t.) To appeal to by an oath.