Aboveboard \A*bove"board`\, adv. Above the board or table. Hence: in open sight; without trick, concealment, or deception. ``Fair and aboveboard.'' --Burke.

Note: This expression is said by Johnson to have been borrowed from gamesters, who, when they change their cards, put their hands under the table.

Source: Webster's Revised Unabridged Dictionary (1913)