金屬蒙上一層暗膜
這一族就是核心畫面本身，動詞看的是變暗的過程，名詞看的是蓋上去的那層東西。
verb · B2
When silver, copper or brass tarnishes, or when air or damp tarnishes it, a thin dark film forms on the surface and the metal stops looking bright.
（金屬）失去光澤
核心畫面
Picture a silver spoon that has been left out on a shelf for a year. Nobody dropped it, nobody scratched it, nobody did anything to it at all — and yet it has gone dark. A thin film has settled over the surface and the shine is hidden underneath. Rub it with a cloth and the brightness is still there, waiting. That is the whole word: something that was bright, a film that quietly covers it, and the shine still sitting under the film.
「tarnish」可以想成一支在架子上放了一年的銀湯匙。沒有人摔它，沒有人刮它，什麼事都沒發生——可是它就是變暗了。…更多收起
「tarnish」可以想成一支在架子上放了一年的銀湯匙。沒有人摔它，沒有人刮它，什麼事都沒發生——可是它就是變暗了。表面上悄悄多了一層薄薄的膜，把亮度蓋在底下。拿布擦一擦，那道光還在，一直都在。這個字要的就是這幅畫面：本來是亮的、慢慢被一層東西蓋住、而光其實還在下面。From the word’s history
The packet's Wiktionary entry traces the word through Middle English ternysshen and Old French ternir ('to make dim, make wan') back to Old High German tarnen, 'to conceal' — the sense of covering something over is in the root itself.
packet 裡的 Wiktionary 資料把它一路追到中古英語 ternysshen、古法文 ternir（使變暗、使失色），再到古高地德語 tarnen（遮蓋）。「蓋住」這個意思本來就在字根裡，這跟現代那層蓋住光澤的暗膜正好對得上。
Wiktionary entry supplied in this packet (source_ref kaikki:3f6f69a190036ae4:910265517:21054)
Two branches
名聲不再發亮
把那層暗膜蓋到名聲上：好名聲像擦亮的銀器，一件事發生後就蒙了一層灰。這是概念上的延伸，方便記憶，不是在說歷史上先有哪個意思。
verb · C1
If an event, a story or a piece of behaviour tarnishes someone's name, record, image or achievement, it leaves people thinking less well of them than they did before.
玷污（名聲）