告

Phono-semantic compound:

口 (구, mouth) — semantic component, representing speech or announcement

牛 (우, ox) — phonetic component, giving the sound

Original form 吿 (U+543F) more clearly shows this composition and is preserved in traditional forms used in Hong Kong and Japanese kyūjitai.

告知 (공지) — notification, announcement

告白 (고백) — confession, declaration

告訴 (고소) — accusation, lawsuit

忠告 (충고) — sincere advice, counsel

警告 (경고) — warning

In Classical Chinese, often implied formally informing superiors (e.g., reporting to a ruler or deity).

吿 (older form, used in Kangxi Dictionary and some traditional orthographies)