This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 嗗 is uncertain. It visually combines 口 (mouth) and 骨 (bone), but the original semantic or phonetic role of these components is unclear.
With 口 (mouth) beside 骨 (bone), imagine a mouth trying to speak but only bone-dry sounds come out—no clear meaning emerges.
For アツ, picture a mouth (口) biting down on a bone (骨) with a sharp 'ats!' sound of pressure: ats -> アツ.
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