Abstract nouns are nouns that refer to intangible things.
A Noun is a word that refers to any thing, place, idea or object. Nouns can be abstract or concrete. Abstract nouns refer to intangible things; whereas concrete nouns refer to tangible things.
Tangible things are things that a person can touch or interact with. Intangible things, on the other hand, are things that a person cannot touch or interact with. These are things that do not have a physical presence and are abstract concepts.
Hence it can be said that abstract nouns are nouns that refer to abstract concepts. An abstract noun is an aspect, concept, idea, experience, state of being, trait, quality, feeling, or other entity that cannot be experienced with the five human senses, i.e. it cannot be seen, heard, touched, smelled or tasted; yet it exists. For example: beauty, bravery, confidence, compassion, ego, love, wisdom, etc.
There is much debate as to what constitutes as an abstract nouns. For example, many people claim that work is an abstract noun. However, there are others that claim that work can be seen and measured; hence it is not an abstract noun. There are many such other examples, such as result, laughter, etc. Due to this, it is important to note that there is a very blurry line that separates an abstract noun from the other nouns.
Examples of Abstract Nouns:
The day was filled with fun and happiness.
The soldier showed great bravery.
The flowers show sadness.
Honesty is the best policy.
Smartness will get you ahead in life.
You need talent to win.
Pride and Prejudice