뭐 함?

The phrase 뭐 함? is a casual or slang-like way of asking “What are you doing?”. It’s an informal contraction of “뭐 해?” (“뭣을 해요?”), which is the standard phrase for asking someone about their actions.

Breakdown:
뭐 (mwo) → “What”
함 (ham) → Casual/slang form of 하다 (do)

Usage & Context:

Texting a friend casually:
친구: 뭐 함?
You: 그냥 쉬고 있어. (“Just relaxing.”)

Checking in on someone’s activity:
A: 뭐 함? 요즘 어떻게 지내?
B: 학교 다니고 있어. (“I’m going to school.”)

Playfully asking what someone is up to:
뭐 함? 심심해 같이 놀자!
What are you doing? I’m bored, let’s hang out!

It’s a very informal way to speak, so it’s best used among friends or in relaxed settings. If you need a polite version, “뭐 해요?” would be more appropriate.