This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
殟 combines 歹 (death, decay) with 昷, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 歹 suggests death or decay, and the right side 昷 looks like a container with a lid. Picture something decaying inside a sealed container, but the exact meaning is uncertain.
For オツ, imagine an odd, decaying object inside the container: odd -> オツ, and the decay 歹 is sealed inside 昷.
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