a poisonous Chinese bird
鴆 refers to a legendary poisonous bird in Chinese folklore, often associated with a toxin derived from its feathers. The meaning is specific to this mythical creature.
鴆 combines 冘 (likely phonetic) with 鳥 (bird), forming a character for a specific poisonous bird. The exact historical development is uncertain, but the structure is typical of phono-semantic compounds.
The bird radical 鳥 on the right is paired with 冘, which looks like a person carrying a burden. Imagine a bird so toxic that even carrying it is dangerous—鴆 is that poisonous bird.
For チン, think of the sharp 'chin' of a bird's beak delivering poison: chin -> チン, and the bird's beak is the source of the toxin.
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poisonfeather bird; zhenniao; zhen; mythical poisonous bird (of ancient China)