還缺一塊的東西
這是核心畫面最直接的用法：把「沒做到完」放在具體的物或事上。
not perfect · adjective · C1
Not completely right or complete, and not as good as something with no faults.
不完美
核心畫面
You can think of it as something that has not been carried all the way through to the end. Latin per- (through) + facere (to make) gives perfect = 'made all the way through'; put im- (not) in front and you get a thing whose making stopped short — the vase with a crack in the glaze, the paint that never reached the corner.
「做到一半、沒有走完全程的東西」。perfect 的拉丁底層是 per-（穿過、到底）加 facere（做），本來的…更多收起
「做到一半、沒有走完全程的東西」。perfect 的拉丁底層是 per-（穿過、到底）加 facere（做），本來的意思是「一路做到完」；前面加上表示否定的 im-，就變成「沒有做到完」。所以 imperfect 不是「壞掉」，而是「還缺一塊」：釉面上有一道裂痕的花瓶、油漆沒刷到牆角、翻譯少了一句話——東西在那裡，但整個過程停在還沒完成的地方，因此比那個完整版差一點。From the word’s history
Latin perfectus (per- 'through' + facere 'to make') = carried through to completion; im- negates it, so imperfect = not carried through.
拉丁文 perfectus 由 per-（穿過、徹底）加 facere（做）構成，意思是「做到底、完成了」；im- 是否定前綴，im- + perfect 就成了「沒做到底」。這條線索同時解釋了兩個現代用法：東西「還缺一塊」，以及文法上動作「還沒結束」。
Wiktionary etymology tree supplied in the payload (PIE *né → Latin im-; PIE *per- → Latin per-; PIE *dʰeh₁- / *dʰeh₁k- → Latin facere), consistent with standard Latin perfectus < perficere.
Two branches
文法上的未完成
同樣是「沒有走完全程」，只是這次談的不是東西，而是時間裡的動作：文法家用 imperfect 標記「過去還在進行、沒有畫上句點」的那一段。
the imperfect tense · noun · C1
The verb form used to talk about an action in the past that was not finished, for example I was eating.
未完成式
原始詞典資料8 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。
imperfectadj/ɪmˈpɜː(ɹ)fɪkt/
- 1
Not perfect.
- Why, then, your other senses grow imperfect.
- Nothing imperfet or deficient left Of all that he Created.
- 2
biologybotanynatural-sciencesUnisexual: having either male (with stamens) or female (with pistil) flowers, but not with both.
- 3
biologynatural-sciencestaxonomyKnown or expected to be polyphyletic, as of a form taxon.
- 4
grammarhuman-scienceslinguisticsRepresenting a continuing or repeated action.
- 5
obsoleteLacking some elementary organ that is essential to successful or normal activity.
- When the prophet Joel was describing the formidable accidents in the day of the Lord's judgment, and the fearful sentence of an angry Judge, he was not able to express it, but stammered like a child, or an amazed, imperfect person.
imperfectnoun/ɪmˈpɜː(ɹ)fɪkt/
- 1
Something having a minor flaw.
- 2
grammarhuman-scienceslinguisticsA tense of verbs used in describing a past action that is incomplete or continuous.
imperfectverb/ɪmpə(ɹ)ˈfɛkt/
- 1
to make imperfect
- 1651, John Donne, Letter to Henry Goodere, in Letters to Severall Persons of Honour, edited by Charles Edmund Merrill, Jr., New York: Sturgis & Walton, 1910, I write to you from the Spring Garden, whither I withdrew my self to think of this; and the intensenesse of my thinking ends in this, that by my help Gods work should be imperfected, if by any means I resisted the amasement.
- Time, which perfects some things, imperfects also others.
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。