How to derive from "zealot"

(Disclaimer: not only I tried googling the answer, I also asked native english speakers, but they couldn't give me a definitive answer).

Basically, In one of my conversations, I said the following sentence:

They haven't contributed much to the world aside zealotness.

Then I got confused, and I realized I don't know what is the "derivative" for this word.

hot -> heat
serious -> seriousness
zealot -> ???

Google remotely suggests zealousness, but it seems that this word actually backs-up the word "zealous" and not "zealot".

So, Is there an actual idiomatic way of saying "zealotness"

Solution 1:

The shortest noun from which zealot is derived is zeal. That is, both the person and the state of mind have direct precursors in Latin, which in turn borrowed them from Greek. Now, zeal has a slightly less specific connotation in modern English; but, brevity being the soul of wit, it will often do the job.

Where you truly need a more specific word, use the fairly common word zealotry.

I should advise against zealotness, which sounds as though the more idiomatic word(s) did not come to mind.