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Webster 1913 Edition

adv.

Above the board or table. Hence: in open sight; without trick, concealment, or deception.

“Fair and aboveboard.”

Burke.

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

See also: above-board and above board

aboveboard ‎(not comparable)

straightforward, transparent