This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
篅 combines 竹 (bamboo) with 耑, which may contribute a phonetic element. The exact historical development is uncertain.
The top component 竹 suggests bamboo, and the bottom 耑 is a shape associated with an end or tip. Picture a bamboo basket or sieve, which fits the kun-reading ざる (bamboo basket).
For スイ, imagine a bamboo basket swaying gently: sway -> スイ, and the basket is made of bamboo.