The word 'agonising' (alternate spelling 'agonizing') is the present participle, present tense of the verb to agonize. The present participle of the verb also functions as an adjective and a gerund (a verbal noun).
Examples:
He's presently agonising over his math homework. (verb)
We had an agonising wait to hear the results. (adjective)
You need to spend less time agonising and more time taking action. (noun)
Yes, the noun astonishment is an abstract noun, a word for an emotional reaction.
Is undergone an abstract noun
The abstract noun is criticism.
The abstract noun is obligation.
Abstract noun of hopeless
Yes, the noun astonishment is an abstract noun, a word for an emotional reaction.
Is undergone an abstract noun
Concrete noun
The abstract noun is criticism.
The noun 'hopefulness' is an abstract noun, a word for an emotion.
The abstract noun is obligation.
Abstract noun of hopeless
Friendship has not abstract noun because It is a abstract noun
The abstract noun form is tourism.
The abstract noun for the adjective vacant is vacantness. Another abstract noun form is vacancy.
The abstract noun for the adjective quick is quickness.
The noun childhood is a singular, common, abstract, compound noun; a word for the time of being a child.