It is not a noun: it is a reflexive singular pronoun.
We usually use this adjective with the verb to be: He was absent yesterday. Meaning that he sould have been there but was not. Also, we can use absent as a verb. He absented himself from the tiring gossip.
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.
Abstract noun of hopeless
The abstract noun is obligation.
Friendship has not abstract noun because It is a abstract noun
The abstract noun form is tourism.
The noun 'Precious' (capital P) is the name of a person, a proper noun, a concrete noun.The word 'precious' (lower case p) is an adjective, a word to describe a noun.The abstract noun form of the adjective precious is preciousness, a common noun.
The abstract noun for the adjective vacant is vacantness. Another abstract noun form is vacancy.