This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form combines the flesh radical ⺼ with 翠, but the original semantic and phonetic roles are unclear.
The flesh radical ⺼ suggests a body part, and 翠 is associated with kingfisher or green. Imagine a greenish body part, but the exact meaning is uncertain.
For スイ, imagine a kingfisher (翠) swooping down to peck at a piece of flesh (⺼): swoop -> スイ, and the bird's swift motion helps recall the reading.
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