verb

• (nautical, transitive) To heave a ship down on one side so as to expose the other, in order to clean it of barnacles and weed, or to repair it below the water line.
  "However, to avoid ſome inconveniencies relating to port duties, which would have been demanded in the port of Canton, and could not, in honour to the British flag, be complied with by us, he adviſed Mr Anſon to put into the harbour of Typa, about ſix miles from Macao, where he might careen his ſhip without diſturbance ; and actually ſent us a pilot to conduct us ſafe to the intended birth."
• (nautical, intransitive) To tilt on one side.
• (intransitive) To lurch or sway violently from side to side.
  "They were not motionless, but swayed to and fro above her head, thronging out of one sky-light into another, as if the universe and not the air-ship was careening."
• (intransitive) To tilt or lean while in motion.

noun

• (nautical) The position of a ship laid on one side.