2. (v. i.) To perceive or apprehend clearly and certainly; to understand; to have full information of; as, to know one's duty.
3. (v. i.) To be convinced of the truth of; to be fully assured of; as, to know things from information.
4. (v. i.) To be acquainted with; to be no stranger to; to be more or less familiar with the person, character, etc., of; to possess experience of; as, to know an author; to know the rules of an organization.
5. (v. i.) To recognize; to distinguish; to discern the character of; as, to know a person's face or figure.
6. (v. i.) To have sexual commerce with.
7. (v. i.) To have knowledge; to have a clear and certain perception; to possess wisdom, instruction, or information; -- often with of.