Definition of swear

• 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.
• v. i. - To give evidence on oath; as, to swear to the truth of a statement; he swore against the prisoner.
• v. i. - To make an appeal to God in an irreverant manner; to use the name of God or sacred things profanely; to call upon God in imprecation; to curse.
• 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.
• v. t. - To put to an oath; to cause to take an oath; to administer an oath to; -- ofetn followed by in or into; as, to swear witnesses; to swear a jury; to swear in an officer; he was sworn into office.
• v. t. - To declare or charge upon oath; as, he swore treason against his friend.
• v. t. - To appeal to by an oath.