The proper response to "How do you do?" is typically to repeat the phrase back: "How do you do?" This is a formal and somewhat old-fashioned greeting used when meeting someone for the first time. Unlike "How are you?" which asks about well-being and invites a detailed response, "How do you do?" is more of a polite introduction phrase meaning "Nice to meet you," and the reply mirrors that sentiment by repeating the phrase. Sometimes people may also respond with "Pleased to meet you" or simply say "I'm fine, and you?" but the traditional and most correct answer is to return "How do you do?"
Additional context:
- "How do you do?" is not used when greeting someone you already know.
- It is very formal and old-fashioned, with many native speakers nowadays preferring simpler greetings like "Nice to meet you."
- The phrase is generally used only in initial introductions and is more about formal etiquette than an actual inquiry into one's condition.
