1.
yeah, uh-huh, yes (informal)
Casual affirmative response used in informal conversations. Much more casual than はい.
「分かった?」「うん。」
"Did you understand?" "Yeah."
2.
hmm, well (hesitation)
Can also express hesitation or thinking while responding.
"Want to go somewhere on the next holiday?" "Hmm, I might have plans. Let me check and get back to you."
うん is the casual equivalent of はい. Only use with friends, family, or in very informal situations.
Related words
- ううん: no (casual negative)
- うーん: hmm (thinking/hesitating)
- うんうん: uh-huh uh-huh (showing you're listening)
Formality scale
Note: Using うん with superiors, teachers, or in formal situations is considered rude.