核心畫面
You can think of sneer as one corner of the top lip pulling up while the eyes stay cold. The mouth moves the way a smile moves, but nothing warm is behind it; the face is saying that whatever it is looking at is beneath it. That one small movement is the whole word. Let the movement happen and you have the verb; hold it still and point at it and you have the noun; put it into a voice instead of a face and you have the mocking tone that can sneer without any lip at all.
sneer 可以想成嘴角往上一扯，眼神卻是冷的。嘴形跟笑一樣，背後卻沒有一點善意；那張臉在說：這東西不值得我認真看待…更多收起
sneer 可以想成嘴角往上一扯，眼神卻是冷的。嘴形跟笑一樣，背後卻沒有一點善意；那張臉在說：這東西不值得我認真看待。整個字就只有這個小小的動作。讓這個動作發生，就是動詞；把它定住、指著說，就是名詞。再把它從臉上搬到聲音裡，嘴角不必動，光靠口氣也一樣能看不起人。From the word’s history
From Middle English sneren 'to mock, scoff at', from Old English fnaeran 'to snort'. The older word names the breath through the nose, which is where the face still starts.
來自中古英文 sneren（嘲笑、譏諷），更早是古英文 fnǣran「噴鼻息」。老字記的是鼻子那一口氣；不屑的時候常常是鼻子先出聲，嘴角才跟著翹起來，跟今天的畫面剛好接得上。
Wiktionary etymology supplied in this packet (kaikki:3f6f69a190036ae4:459445229) for 'sneer': Middle English sneren < Old English fnǣran < Proto-Germanic *fnesaną