A favorite friend, a convivial associate. Now on its way to obsolescence, the adjective “boon” comes from the French bon, for “good,” and has meant “jolly” since the twelfth century. As for the pairing with “companion,” several sources cite the Roman epigrammist Martial, who wrote nulli tefacias nimis sodalem, which has been translated as “to no man make yourself a boon companion.” The association with drinking was made explicit by John Arbuthnot (The History of John Bull, 1712): “A boon companion, loving his bottle and his diversion.”