擋人的規定
離字面最近的一組：prohibit 本來就是用規定禁止，所以規定當然是最原本的擋門人。
adjective · C1
Used about a rule, a law or a system that stops people from doing things.
禁止性的
核心畫面
Something is standing in the doorway. You were going to walk through, and now you are not. The word never names the thing that blocks you in the same breath as the blocking: sometimes it is a rule, sometimes a number on a price tag, sometimes a rival so far ahead that the other results cannot get past. In every case prohibitive describes the blocker, not the person turned away, and it says the door is closed rather than merely heavy.
可以想成有個東西站在門口。你本來要走進去，現在走不進去了。這個字每次描述的都是「擋住你的那個東西」，不是被擋住的人。…更多收起
可以想成有個東西站在門口。你本來要走進去，現在走不進去了。這個字每次描述的都是「擋住你的那個東西」，不是被擋住的人。擋住你的可能是一條規定，也可能是價目表上的數字，也可能是一個領先太多的對手。畫面都一樣：門是關的，不只是重。抓住這個「擋在門口」的畫面，三個用法就連成一條線。From the word’s history
The source analyses the word as prohibit + -ive, where -ive names a tendency, giving 'tending to prohibit'. That is exactly the blocking picture. The source does not gloss the older Latin form, so nothing beyond this layer is claimed here.
資料把這個字拆成 prohibit 加 -ive，-ive 表示「傾向於做某件事的」，合起來是「會去禁止的」。這正好就是擋在門口的畫面。再往前的拉丁文，資料沒有給解釋，所以這裡不多說。
packet Wiktionary etymology_text for prohibitive: 'By surface analysis, prohibit + -ive'; kaikki:3f6f69a190036ae4
Three branches
擋人的代價
換成數字來擋門：沒有人禁止你買，但價錢站在那裡，結果跟被禁止一樣。
adjective · C1
Used about a price or a cost that is so high that it stops people from buying something or doing something at all.
貴到讓人放棄
把別的可能擋掉的領先
同一個畫面搬到比賽場上：領先太多的人像高價一樣，把其他結果擋在門外。
adjective · C1
Used in American English about a person or team that is so far ahead that the other results feel shut out. It nearly always appears in the phrase prohibitive favorite.
穩贏的大熱門