This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
搩 combines 扌 (hand) with 桀, but the historical origin and meaning are uncertain. It may be a phono-semantic compound, but the exact development is unclear.
With no clear meaning, picture a hand 扌 beside the complex 桀 shape, as if handling something mysterious or unknown.
For ケツ, imagine a hand reaching out to catch a mysterious object, and the sound of the catch is a sharp 'ketsu' — ketsu -> ケツ.
distance between the thumb and middle finger of an extended hand