那根短棍，以及揮下去的一下
這一家就是核心畫面本身：先有物品，再有拿物品做的動作。
noun · C2
A short, heavy stick or metal bar, often covered in leather, that someone carries to hit people with. It is small enough to hide in a pocket or a bag.
短棍
核心畫面
You can picture one short piece of heavy pipe, wrapped in leather, small enough to sit unseen in a coat pocket. Everything in this group can be traced back to that single object: the thing itself, the act of swinging it, and the feeling of standing still while somebody holds it over your head.
可以想成一根短短的、沉甸甸的棍子，外面包著皮，短到能塞進外套口袋而不被看見。這一組意思都可以從這根棍子看出來：棍子本…更多收起
可以想成一根短短的、沉甸甸的棍子，外面包著皮，短到能塞進外套口袋而不被看見。這一組意思都可以從這根棍子看出來：棍子本身、揮下去的動作，還有被人舉著棍子、自己只能站在底下的那種壓迫感。棍子的重點一直是「短而重」——短所以藏得住，重所以一下就夠。From the word’s history
Probably from Romani košter, 'stick'. Wiktionary marks the origin as probable, not certain.
字典說它可能來自羅姆語（吉普賽語）的 košter，意思就是「棍子」。來源只標成「可能」，所以不能講得太滿。但這條線索跟核心畫面是一致的：這個字從頭到尾講的都是一根拿在手上的短棍。
Wiktionary entry for cosh (etymology 1): "Probably from Romani košter (stick)."
Two branches
棍子懸在頭上：壓力
同一根棍子，但停在半空中沒有落下。把畫面停在那一刻，剩下的就只有壓力。
noun · C2
If you are under the cosh, you are in a hard situation with a lot of pressure on you, and the pressure keeps going instead of passing quickly.
壓力很大