to spy upon, to give information, shrewd
詗 centers on covert information gathering: spying, secretly reporting, or acting shrewdly to obtain hidden knowledge.
詗 combines 言 (speech) with 冋, which likely contributes a phonetic element. The exact historical development is uncertain, but the structure suggests a connection to spoken information gathering.
Words (言) paired with a spy-like shape (冋) suggest someone using speech to pry into secrets. Imagine a shrewd informant whispering reports.
For キョウ, picture a spy in Kyoto (キョウ) gathering information: Kyoto -> キョウ, and the spy's words (言) are the key.