to act contrary to
佷 centers on acting in opposition or defiance: going against what is expected or required. Its meaning is narrow and rare, with no clear broader conceptual cluster beyond contrarian action.
佷 combines the person radical 亻 with 艮. The exact historical development is uncertain, but it likely originally expressed a person acting stubbornly or contrary, with 艮 possibly contributing a phonetic or semantic element.
A person 亻 standing beside 艮, which looks like a stubborn root or a halted step. Imagine someone refusing to move, acting contrary to instructions.
For コン, picture a person acting contrary and getting a con (コン) job punishment: con -> コン, and the person stubbornly resists.