This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
虤 is composed of two 虎 (tiger) components side by side. The exact historical development and original meaning are uncertain.
Two tigers facing each other, perhaps suggesting conflict or intensity, but the meaning is unclear.
For ガン, imagine two tigers glaring at each other with a deep, guttural growl: the growl sounds like ガン.
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