* Clach-taobh: This literally translates to "stone-side" and would work well for a rocky hillside.
* Taobh-cnoc: This translates to "hill-side" and is a more general term. It's probably the closest direct equivalent.
* Leithid: This means "slope" or "side," and could be used depending on the context. You might say something like "lethid cnoc" (slope of a hill).
The best choice will depend on the specific context and the character of the hillside. If you can provide more detail about the hillside you're describing, a more precise translation can be offered.