Hesitation sound used when thinking, pausing, or showing mild doubt. Similar to English 'um' or 'well'.
See also: うん
Um, let me think for a moment.
うーん、どっちがいいかな。
Hmm, which one is better?
nuh-uh; no
Only with reading ううん
Casual negative reply, often with a falling intonation. Used to deny or refuse something informally. The reading is restricted to ううん; the long-vowel spelling うーん is not typical for this sense.
「もう食べた？」「ううん、まだ。」
"Did you eat already?" "Nope, not yet."
Sound made when straining, lifting something heavy, or feeling sudden pain. Similar to English 'oof' or a grunt.
See also: うん
うーん、この箱重い！
Oof, this box is heavy!
ううん is the casual, everyday way to say 'no' among friends or family, while いいえ is the polite, formal equivalent.
ううん is an even more casual, often childish or feminine way to say no, whereas いや sounds neutral in casual speech.
うん is the casual affirmative ('yeah'), while ううん (sense 2) is the casual negative ('nuh-uh'); they differ mainly by vowel length and intonation.
いいえ is the polite, formal way to deny or refuse something, while ううん is its casual spoken counterpart.
Standard hiragana spelling for the hesitation sound and the casual negative reply.
Long-vowel-marked spelling often used for the hesitation or groaning sense; less common for the negative reply.
Katakana spelling occasionally seen in manga or casual writing for the hesitation or groaning sense.
An imitative vocal interjection representing a groan or sustained “uu” sound. From uses for exertion, pain, and hesitation it also developed contextual response meanings, including negation.