proper name
晁 is a rare kanji used primarily as a proper name. Its standalone meaning is unclear beyond that naming function.
晁 combines 日 (sun) with 兆, which likely contributes a phonetic element. The exact historical development is uncertain, and the character is rare in modern Japanese.
The sun 日 rises over a shape 兆 that looks like a sign or omen. Picture a name written in the morning light, marking a person's identity.
For チョウ, imagine a person named Chou whose name is written with the morning sun 日 above the sign 兆: Chou -> チョウ.