What does ううん mean?
ううん is a Japanese interjection meaning “um; er; well” in English. It can also be translated as “nuh-uh, oof” depending on context. It is written as ううん in hiragana, and uun in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
ううん、由美ちゃんが魔法瓶に入れて、部室に持って来てくれたの。
No, Yumi put it in a thermos flask and brought it into the club room.