This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
匞 combines 匚 (box/enclosure) with 工 (work/craft). The exact historical development is uncertain, but it likely relates to a craftsman or container for tools.
The outer enclosure 匚 is like a toolbox, and inside is 工, the symbol for work or craft. Picture a craftsman's toolbox holding the tools of the trade.
For ショウ, imagine a craftsman showing off his toolbox: show -> ショウ, and the 匞 holds his craft.