broomstick
篲 centers on a broomstick: a long-handled brush used for sweeping. The meaning is narrow and concrete, referring to the tool itself.
篲 combines 竹 (bamboo) with 彗, which likely contributes both sound and the idea of sweeping. The bamboo top suggests a broom made from bamboo.
The bamboo 竹 top over 彗 looks like a bundle of bamboo twigs tied to a handle: a broomstick ready to sweep.
For スイ, imagine sweeping so smoothly that the broom seems to 'swish' across the floor: swish -> スイ, and the broomstick glides.