(1):
(adv.) Against the affirmative side; in opposition; on the negative side; - The antithesis of pro, and usually in connection with it. See Pro.
(2):
(v. t.) To know; to understand; to acknowledge.
(3):
(v. t.) To study in order to know; to peruse; to learn; to commit to memory; to regard studiously.
(4):
(v. t.) To conduct, or superintend the steering of (a vessel); to watch the course of (a vessel) and direct the helmsman how to steer.