This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 曻 is uncertain. It visually contains 曰 and 舛, but the original component relationship is unclear.
The top 曰 can suggest speaking or saying, and the bottom 舛 looks like two feet dancing or moving. Without a clear meaning, picture a story told through dance.
For ショウ, imagine a show where dancers move their feet (舛) while a narrator speaks (曰): show -> ショウ.