There is not rule for changing nouns to abstract nouns. A noun is either a concrete noun or an abstract noun depending on what the word means.
Concrete nouns are words for things that can be experienced by one or more of the five senses; it can be seen, heard, smelled, tasted, or touched.
Abstract nouns are words for things that can't be experienced by any of the five senses; they are words for things that we know, understand, believe, or feel emotionally.
Sometimes concrete nouns are used in an abstract context, such as 'road' a concrete noun used as 'the road to paradise', an abstract context. But the word road does not change, only it's use changes.
The abstract noun form is tourism.
The abstract noun form of the adjective unique is uniqueness.
The abstract noun form of the concrete noun friend is friendship. The abstract noun form of the verb to serve is service. The abstract noun form of the adjective weary is weariness. The abstract noun form of the concrete noun child is childhood.,
The abstract noun form for the adjective truthful is truthfulness.The word 'truthful' is the adjective form of the abstract noun truth.
The abstract noun form of the adjective 'attentive' is attentiveness.A related abstract noun form is attention.
The abstract noun form is tourism.
The abstract noun form of the adjective unique is uniqueness.
The abstract noun form of the concrete noun 'thief' is thievery.The abstract noun form of the concrete noun 'infant' is infancy.The abstract noun form of the concrete noun 'coward' is cowardice.The abstract noun form of the adjective 'urgent' is urgency.
The abstract noun form of the concrete noun friend is friendship. The abstract noun form of the verb to serve is service. The abstract noun form of the adjective weary is weariness. The abstract noun form of the concrete noun child is childhood.,
The abstract noun form of the concrete noun 'women' is womanhood.
The abstract noun form for the adjective truthful is truthfulness.The word 'truthful' is the adjective form of the abstract noun truth.
The abstract noun form of the adjective 'legal' is legality.A related abstract noun form is the informal noun legalese.
The abstract noun form of the adjective 'attentive' is attentiveness.A related abstract noun form is attention.
The abstract noun form of the adjective 'polite' is politeness.
The abstract noun form for the adjective suspicious is suspiciousness.A related abstract noun form is suspicion.
The abstract noun form of the adjective terrible is terribleness.A related abstract noun form is terror.
The abstract noun form of the adjective 'tenacious' is tenaciousness.A related abstract noun form is tenacity.