- 1兩面人、當面一套背後一套（也可說「表裡不一」）
A two-faced person says one thing to you and the opposite about you when you are not there. They are friendly to your face and behind your back — and the word says you cannot trust them. It is a strong accusation, stronger than 'dishonest', because it is about someone who thought they were a friend. That is why it hurts: the two-faced person is usually someone close, in your office, in your class, in your group of friends. It is informal and always negative; you use it about people, not about ideas or companies, and almost never about yourself. The image is of a person wearing two faces, one for each audience — an image that goes back a long way, to the Roman god , who was pictured with a face at the front and a face at the back.
two-faced 用來說人當面一套、背後一套：你在面前很友善，不在場時卻說相反的話。它的語氣比 dishonest（不誠實）重很多，因為重點是辜負了原本以為是朋友的人。常見說法是「a two-faced person」（表裡不一的人），通常指身邊很熟的人，例如同事、同學或朋友圈裡的人。
這是口語，評價一定是負面的，只用來形容人，很少用在想法或公司上，也幾乎不會拿來形容自己。這個圖像來自羅馬神 Janus，他的前後各有一張臉。
From the word’s history
From two + faced, modelled on earlier twi-faced.
由 two 加 faced 組成，仿照更早的 twi-faced。
組成two + face + -ed（帶有……的）— 'having two faces'. English had an older version, 'twi-faced', with the same idea; 'twi-' was the old way of saying 'two'.
同家族的字
- twothe number itself
- facedfrom 'face'; the same '-ed' pattern appears in bare-faced, red-faced, straight-faced
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，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。
two-facedadj/ˈtuːˈfeɪst/
- 1
Having two faces or plane surfaces.
- 2
Deceitful, duplicitous.
- 3
Hypocritical.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。