> Show me an example of a type class with five functions and then how I can reuse it while overriding one of these five.

Huh? As I'm sure you're aware "type classes" != "classes", so I'm not sure why you're expecting them to be 'interchangeable' in this manner. It would be better to ask for some functionality (not a mechanism, as you're asking) and then show how one could be achieved[1] in one, but not the other.

Personally, I think any kind of implementation override is a code smell. If you need common functionality, just have a plain function outside your class and use that from both interface overrides.

[1] "Elegantly" or "expressively", one presumes. Of course everything can be achieved in any TC language.