This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
臗 combines ⺼ (flesh/body part) with 寬, which likely contributes the sound. The exact historical development is uncertain.
The left side ⺼ suggests a body part, and the right side 寬 is a phonetic component. Without a clear meaning, picture a mysterious body part labeled with the sound コン.
For コン, imagine a con artist pointing at the body part ⺼ and saying 'con' to distract you: con -> コン.