サン, す.い

acid, bitterness, sour, tart

JLPT1 G5 S14 F1218

As per # as described in (stand erect) + 酉 alcohol → *sour* alcohol that, when imbibed, causes the body to stiffen (= become erect) in revulsion → *acid* (← sour or souring agent) → *severe*.

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