Which one should you use?
You should choose your phrase based on where the object is located: use 이게 뭐야? if the object is near you (What is this?), but use 그게 뭔데? to refer to something near the listener or a topic that was previously mentioned.
Is there a formal and an informal way to say it?
The default form 그게 뭔데? is casual and can sound slightly blunt or impatient depending on your tone. For a more neutral informal way to ask, you can use 그게 뭐야? In formal or professional settings, use 그게 무엇입니까? or 그것은 무엇입니까?
How does it change in a sentence?
While 그게 뭔데? is a common contraction, you can also use the slightly more neutral informal form 그게 뭐야? In formal contexts, the full form 그게 무엇입니까? is appropriate.
How do you pronounce it?
geuge mwonde?
Did you know?
- The casual form 그게 뭔데? ends with 데, which can actually function as a way to express a sense of curiosity or even a slight challenge to the listener's explanation.
- While 그게 뭔데? is a common way to ask 'what is it?', using it with someone older or in a higher social position is considered a major social blunder.
- If you use a sharp, rising intonation with 그게 뭔데?, it can transform from a curious question into an aggressive 'So what is it?' that sounds confrontational.
Examples in context
- 갑자기 그게 뭔데?gapjagi geuge mwonde?What is that all of a sudden?
Example conversation
Hyunwoo and Seoyeon are looking at a strange package on the table.
- 현우 Hyeon-woo서연아, 저기 상자 좀 봐.Seoyeon-a, jeogi sangja jom bwa.Seoyeon, look at that box over there.
- 서연 Seo-yeon그게 뭔데?geuge mwonde?What is it?
- 현우 Hyeon-woo내 선물 같아.nae seonmul gata.It looks like my gift.
- 서연 Seo-yeon진짜 궁금하다.jinjja gunggeumhada.I'm really curious.