A gomeral is a stupid or foolish person in Scots. I’m sure you are not a gomeral, but I’ll bet you know one.
Everyone knows a great gomeral, but they may not have known that’s what we call it in Scots. It’s a good Scottish word to express what an eejit you’re talking to. Honestly, what a lame brain, thicko, idiot you are. You’re nowt but a great gomeral!