The relationship between 羞 and 醜 Since 醜 is the traditional version of 丑, why is the lower part of a traditional 羞 丑 but not 醜?
I found this 羞,

(會意兼形聲。據甲骨文,以手持羊,表示進獻。小篆從羊,從醜,醜亦聲。“醜”是手的訛變。本義:進獻)

But it doesn't explain why it is 丑.
羞 didn't originally mean shame/shy and 丑 didn't originally mean ugly.
丑 is originally a hand with curled fingers, later borrowed to become an earthly branch. Ugly, and all its associated meanings like disgrace, shame, and even clown were originally 醜, which became replaced with 丑 in 'simplified' Chinese. I believe 丑 was borrowed as part of 羞.
羞 is a hand 手 holding a lamb 羊, to offer it as a sacrifice or for food, originally meaning &quot;offering&quot;. The hand got changed into 丑, which doubles up as phonetic component.
Offering is now written as 馐.
羞 earlier on had its meaning shifted to become shame or shy, possibly because lambs and sheep are shy and timid creatures, while ugly was still written as 醜.
https://www.zdic.net/hans/%E9%A6%90
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