This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
簙 combines 竹 (bamboo) with 博, but the exact historical development and original meaning are uncertain.
The top 竹 suggests bamboo, and the bottom 博 suggests breadth or a game. Picture a broad bamboo board used for an old game like sugoroku.
For ハク, imagine playing a bamboo game with a friend named Haku: Haku -> ハク, and you both enjoy the broad board.