ナイチチ

Meanings

very small breasts; flat chest

usually written using kana alonecolloquial

Colloquial and often used in casual or humorous contexts. Compare with 微乳 (びにゅう), which is a more neutral term for small breasts.

Kanji

無nothingness, none, ain't
乳milk, breasts

Related words

微び乳にゅう
微乳 is a more neutral, descriptive term for small breasts, while ない乳 is colloquial and can carry a humorous or self-deprecating tone.
貧ひん乳にゅう
貧乳 literally means 'poor breasts' and is a common slang term for small breasts, often used in anime/manga contexts. ない乳 is more direct and emphatic about the lack of size.

Built from

ない+乳ちち

Written forms

ない乳ちち
Kana-mixed spelling; usually written in kana.
ナイチチUsage100%
kana-only spelling
Katakana spelling, sometimes used for emphasis or in informal contexts.
無ない乳ちち
Kanji spelling using 無い; rare and not commonly used.

Etymology

Compound of ない (nai, 'not exist') and 乳 (chichi, 'breasts'), literally 'no breasts'. The exact origin is uncertain, but it likely arose as internet slang or colloquial expression.