This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 貇 is uncertain. It combines 豸 (a beast radical) with 艮, but the original semantic and phonetic roles are unclear.
With no clear meaning, picture a mysterious beast (豸) with a stubborn, rooted quality (艮) — an unknown creature whose nature is hard to define.
For コン, imagine a con artist trying to sell you this unknown beast: con -> コン, and the beast remains a mystery.