boarder

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One who boards, especially.
• noun One who pays a stipulated sum in return for regular meals or for meals and lodging.
• noun One who goes on board a vessel as part of an assault or military action.
• noun A person who rides a board, such as a snowboard or surfboard, as a sport.

from The Century Dictionary.

• noun One who boards.
• noun plural On a man-of-war, the officers and men detailed to attack an enemy by boarding. They are armed with cutlases and pistols.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who has food statedly at another's table, or meals and lodgings in his house, for pay, or compensation of any kind.
• noun (Naut.) One who boards a ship; one selected to board an enemy's ship.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A pupil who lives at school during term time.
• noun Someone who pays for meals and lodging in a house rather than a hotel.
• noun nautical A sailor attacking an enemy ship by boarding her, or one repelling such attempts by an enemy.
• noun Someone who uses a snowboard

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a tenant in someone's house
• noun a pupil who lives at school during term time
• noun someone who forces their way aboard ship