castrate pig
豶 refers specifically to a castrated pig. The meaning is narrow and technical, with no broader conceptual center beyond this single action applied to a pig.
豶 combines 豕 (pig) with 賁, which likely provides the sound. The character is a phono-semantic compound specifically coined for the act of castrating a pig.
A pig 豕 next to 賁 (which can suggest 'adorn' or 'energetic') might be remembered as a pig being 'altered' or 'decorated' through castration.
For フン, imagine the fun (フン) a pig might have after being castrated—though it's a stretch, the sound 'fun' can hook the reading.
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