When combined, 卖国贼 (màiguózéi) creates a powerful and literal image: a “thief who sells the country.” This is far more visceral than the English word “traitor.”
The term 卖国贼 is deeply embedded in the narrative of modern Chinese history, particularly the “Century of Humiliation” (百年国耻, bǎinián guóchǐ) from the mid-19th to mid-20th century. During this period, China faced repeated invasions and was forced into unequal treaties by foreign powers. Figures who collaborated with these invaders or were seen as sacrificing national interests were branded with this term, ensuring their eternal infamy in the collective memory.
This term is extremely strong and is used with great deliberation. It is almost never used in casual conversation.