also: ききゃく
noun
A somewhat formal or literary term for a player of shogi or go. In everyday speech, 将棋指し or 碁打ち are more common.
彼は若いながらも名の知れた棋客だ。
Though young, he is a well-known shogi/go player.
江戸時代の棋客たちの記録が残っている。
Records of Edo-period shogi and go players remain.
棋士 is the standard modern term for a professional shogi or go player, while 棋客 is more literary and less common.
将棋指し is a common, everyday term for a shogi player, whereas 棋客 is more formal and can also refer to go players.
碁打ち is a common term for a go player, while 棋客 is a broader, more literary term covering both shogi and go players.
Composed of 棋 (board game, especially shogi or go) and 客 (person, guest). The exact historical derivation is uncertain, but it has been used to refer to players of these games.