What do you mean?
It's another verb " to finish"
Ah, I see, I looked it up just now on the GPC, I'm not familiar with it because it's an alternate version of "Cwblhau".
cwpla for cwblhau (completing, finishing) is a spoken form from the Gwentian (Gwenhwyseg) dialect. You may hear it in the wild in south-central and south-east Wales.
the only correct choice was orffen not gorffen.
That has now been fixed - it should be gorffen unless there is a particular reason to mutate it. (The correction may take a little while to be released into the app.)