三十八 (sānshíbā): thirty-eight, 38

Two-character 三八 sānbā has a famous double life: it's the date of International Women's Day (三八节, March 8) yet in Taiwanese / southern slang it's an insult for a flighty woman. The full three-character 三十八 simply means '38' and avoids the slang reading.

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三八式 sānbā shì also refers to the Japanese Type 38 Arisaka rifle, ubiquitous in Chinese WWII films — '三八大盖' is the standard nickname.