to spit out
咅 centers on forcefully ejecting something from the mouth: spitting out. It is a rare standalone kanji, but its shape appears as a component in more common characters.
咅 combines 立 (stand) and 口 (mouth), likely suggesting the action of standing and expelling something from the mouth. The exact historical development is uncertain.
Picture a person standing (立) and forcefully spitting something out of their mouth (口). The top 立 is the upright posture, and the bottom 口 is the open mouth ejecting.
For トウ, imagine spitting out a tough piece of food: tough -> トウ, and the mouth 口 under the standing figure 立 expels it.
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