This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
匌 combines 勹 (wrap) with 合 (join). The exact historical development is uncertain, but it likely expressed the idea of wrapping or enclosing something joined together.
The outer 勹 wraps around 合, like a container holding joined parts. Without a clear meaning, picture it as a mysterious wrapped package.
For コウ, imagine the wrapped package (匌) is a gift from a friend named Kou: Kou -> コウ.