This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
埩 is a rare character combining 土 (earth) with 争. The exact historical development is uncertain, and it may have been used in specialized contexts.
The left side 土 suggests earth or soil, and the right side 争 can suggest contention. Picture two farmers arguing over a patch of land, tilling it in dispute.
For ショウ, imagine the farmers shouting at each other while tilling: shout -> ショウ, as they argue over the soil.