材料變硬：字面上的那個畫面
這一支就是核心畫面本身，沒有比喻。
verb · C1
To treat cloth, paper or other material so that it becomes firm and does not bend easily.
使（材料）變硬挺
核心畫面
Picture a soft cotton collar lying flat on a table. Brush starch over it, let it dry, and it stands up on its own — the same cloth, but it will not flop any more. That change is stiffen: something that used to give way now holds its shape and resists being bent. Put that change in a body and you get the two everyday uses: a person who goes still for a second when a name is mentioned, and a back that will not bend the morning after carrying boxes. Put it in something you cannot touch — a rule, a position, a person's determination — and you get the same picture again: it has stopped giving way.
可以想成一片軟軟的棉布領子平放在桌上。刷上漿、等它乾，它就自己立起來了——還是同一塊布，但它不再垂下去。stiffe…更多收起
可以想成一片軟軟的棉布領子平放在桌上。刷上漿、等它乾，它就自己立起來了——還是同一塊布，但它不再垂下去。stiffen 講的就是這個變化：本來會軟、會彎的東西，現在撐得住形狀，不肯被折。把這個變化放進身體，就得到兩個日常的用法：有人提到某個名字，一個人整個僵住一秒；或是搬完箱子的隔天，背彎不下去。把它放進摸不到的東西上——規定、立場、一個人的決心——畫面還是一樣：它不再讓步了。From the word’s history
Wiktionary records stiffen as Middle English stifnen, that is stiff plus the ending -en. English uses that ending to build change-of-state verbs: soft becomes soften, hard becomes harden, wide becomes widen. So the word is literally make stiff or become stiff, which is exactly the collar on the table.
來源資料寫 stiffen 來自中古英語 stifnen，等於 stiff 加上字尾 -en。英文用 -en 造了一整排表示「變成／使變成」的動詞：soft→soften、hard→harden、wide→widen。所以這個字字面就是「變硬、使變硬」，正好就是桌上那片上了漿的領子。
Wiktionary entry for stiffen (packet evidence: kaikki:3f6f69a190036ae4:213729155, etymology_text: From Middle English stifnen, equivalent to stiff + -en)
Three branches
身體變硬：一瞬間的，和累積出來的
同一個變化發生在人身上，本來能動的變得不動、不彎。
verb · B2
If you stiffen, your body suddenly goes firm and still for a moment, usually because you are angry, worried, or do not want to be touched.
僵住
抽象的東西變硬：規定、立場、決心
把「不肯彎」這件事搬到摸不到的東西上，材料換了，畫面沒變。
verb · C1
To become stronger, stricter or more determined, or to make something become like this.
加強、變強硬