How does the hook in 甩 negative 用's meaning?

Question

I read 甩 - Wiktionary, and screenshot Yellowbridge. 甩 appears the antonym of 用, and the hook (that I marked with the green arrow) appears the only difference between their logograms.

1. What's the correct term for this "hook"?

2. Please see the title.

The Cantonese reading is probably unrelated, though it may reflect a descendant of the archaic pronunciation *rut and hence be cognate with Mandarin. Either way, it is evidently from the same source as Min Nan 甪 (lut, “to come off, to slip loose”), Zhuang lot (“to come loose and drop off (due to loose tying)”), and Vietnamese lột (“to peel, to strip off”).

https://chinese.stackexchange.com/a/38716 spurred this question.

Answer 1

What's the correct term for this "hook"?

“乚” is named “cjk stroke swag” (u+31df), as used in “己”, the third stroke.

https://www.unicode.org/charts/PDF/U31C0.pdf

in chinese, it’s described as “豎曲鉤”, by the 教育部 異體字字典.

< https://dict.variants.moe.edu.tw/variants/rbt/word_attribute.rbt?quote_code=QTAyNjI4>

The Cantonese reading is probably unrelated

such claiming is wrong. it’s a cantonese character (粵字)

in 廣東通志 卷五十一, page 30 mentioned:

物之脫者曰甩・倫粒切・此粤字之隨俗撰出者也

https://archive.org/details/06041865.cn/page/n29/mode/1up

have fun :)