Ha I tried "Punyakah", either it's not a word, or this translation is missing.
When do I know when I can just add the "-kah" suffix to a word?
I've noticed it not being used very much, so it might sound ridiculous to a native speaker's ear?
Technically, you can use "punyakah", but it's rarely used. You would sound very formal, at least where I live.
The US calls it bell peppers but most countries calls it capsicum.
Capsicum may come from Latin capsa, meaning 'box', presumably alluding to the pods