dongsaeng

Dongsaeng is Korean for younger sibling or younger person. Used widely in Korean and K-pop contexts. Not concerning. If your kid uses it constantly, ask them where they first heard it, not to police their speech but to understand which online community they are in. Most slang of this kind moves through TikTok and group chats, so seeing it in your child's vocabulary just means they are plugged into normal teen internet culture.

Dongsaeng is a Korean noun meaning younger sibling or, more broadly, a younger person (used by older people for those younger than them). Use in Korean cultural and K-pop contexts. Formal equivalent: "younger sibling," "younger one." Common non-native mistake: applying only to literal siblings; in Korean usage, age-based relationships extend the term to friends, classmates, and colleagues younger than the speaker. Read or listen to the word in context several times before trying it yourself; the right register is harder to learn than the dictionary meaning.