What will be the noun for agony using suffixes?

There isn't a direct noun form of "agony" created by simply adding suffixes. "Agony" itself is already a noun.

However, you could use related words:

* Agonizing (adjective): This describes something that causes agony. You might refer to the "agonizing pain" or the "agonizing wait."

* Agonist (noun): This refers to someone who competes in a contest or struggle. You could say "He was a valiant agonist in the fight."

You could also use other nouns to describe the feeling of agony:

* Pain

* Suffering

* Torture

* Distress

* Misery

The best choice depends on the specific context and the nuance you want to convey.