This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
僶 combines the person radical 亻 with 黽, but the exact historical development and original meaning are uncertain.
A person 亻 beside the complex 黽 shape. Without a clear meaning, picture a person trying to decipher an ancient, frog-like glyph.
For ビン, imagine a person 亻 peering into a bin full of mysterious 黽-shaped objects: bin -> ビン.