時間上沒有終點
把「沒有界線」放在時間軸上：事情繼續下去，但沒有人在哪一天畫上停止線。
with no end date · r · C2
For a period of time with no arranged end; nobody has said when it will stop.
無限期地
核心畫面
One way to picture it: a line drawn without anyone marking where it ends. The word comes from 'definite' — something with a boundary set around it — plus 'in-' to take that boundary away. So indefinitely means doing something with the edge missing: no end date on the calendar, no exact figure written down.
一條線畫出去，但沒有人在末端畫上句點。這個字的骨架是 definite（有界線、被框定的）加上否定的 in-，所以 …更多收起
一條線畫出去，但沒有人在末端畫上句點。這個字的骨架是 definite（有界線、被框定的）加上否定的 in-，所以 indefinitely 的動作比較像「把那條界線拿掉」。可以是時間上的邊界不見了——沒人說什麼時候停；也可以是內容上的邊界不見了——沒有人把話說到那個清楚的點上。共通的感覺都是：東西還在，只是框不見了，所以你抓不到它的邊在哪裡。From the word’s history
From Latin 'definire' (to set bounds to, from 'finis' = limit, boundary) → 'definite' = bounded, fixed; the negative prefix 'in-' removes that boundary, and '-ly' turns it into a manner adverb.
字根來自拉丁文 finis（界線、終點）：definire 是「在四周畫界線」，所以 definite 是「有界線的、被框定的」。加上否定的 in- 就是把那條界線拿掉，再加 -ly 變成描述方式的副詞。這條線索直接解釋了現代的兩個用法——不管是時間沒有終點，還是說法沒有明確的輪廓，都是同一個「界線缺席」的畫面。
Oxford English Dictionary / Etymonline entries for 'definite' (< Latin definire, finis 'boundary') and the prefix 'in-'
Two branches
說法上沒有明確輪廓
同一個「界線缺席」換到語言上：話說出來了，但沒有把細節框到清楚的位置，所以聽的人抓不到確切的形狀。
vaguely · r · C2
In a way that does not give clear or exact details, so people still do not know the exact facts.
不明確地
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
indefinitelyadv/ɪnˈdɛfɪnɪtli/
- 1
In a manner that is not definite.
- an indefinitely determined fossil
- 2
For a long time, with no defined end.
- It was a dark, horsehairy place with a sort of abandon-hope atmosphere that seemed suitable for people that had no money, and who were going indefinitely into pawn.
- For it would surely improve the domestic standing of Prime Minister Benjamin Netanyahu, an unbudgeable hawk, and thereby indefinitely delay peace on that Middle Eastern front.
- 3
Forever.
- Even assuming, however, that for economic reasons capitalism cannot last indefinitely, it would still not follow that it must be replaced by Marxian socialism.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。