This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
誙 combines 言 (speech) with 巠, which likely contributes the sound. The exact historical meaning is uncertain, and the character is rare in modern Japanese.
With 言 (words) beside 巠, imagine unclear speech that is hard to grasp, reflecting the kanji's uncertain meaning.
For コウ, picture a person named Kou trying to speak (言) but only producing vague sounds: Kou -> コウ.