1.
no; nope (casual negative)
A casual way of saying 'no' in informal conversation. Softer and more casual than いいえ. Often used among friends and family.
2.
not at all; don't mention it
Used to downplay thanks or a compliment, similar to 'it's nothing' or 'no problem' in English.
A very common informal interjection. Pronounced with a nasal, rising-then-falling intonation that distinguishes it from うん (yes). The intonation is crucial — with a flat or rising tone, it could be confused with a hesitation sound.
Pronunciation
The pitch pattern matters. ううん (no) has a distinctive nasal, falling pattern, while うん (yes/yeah) is shorter with a rising or flat tone. In writing, the longer ううん is clearly distinguished from the shorter うん.
Similar words
- いいえ: the polite "no"
- いや: casual "no", blunter than ううん, which is soft
Usage
Primarily used in face-to-face casual conversation. In written Japanese, appears in dialogue in manga, novels, and text messages. Not appropriate in formal settings.