This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
凘 combines the ice radical 冫 with 斯, which likely contributes a phonetic element. The exact historical development is uncertain.
The ice radical 冫 suggests something related to cold or ice, but the overall meaning is unclear. Picture a frozen, obscure shape that resists easy interpretation.
For シ, imagine a sheet of ice (シート, shiito) covering the mysterious right side: sheet -> シ, and the ice radical reinforces the cold image.
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