This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
詝 combines 言 (speech) with 宁, which may contribute sound. The exact historical development is uncertain.
With 言 (speech) on the left and 宁 on the right, imagine a word that is stored or kept, but its meaning is unclear.
For チョ, picture a child (チョ sounds like 'cho' in 'child') trying to speak (言) but the words are uncertain.