Abstract Concepts:
* Happiness: A feeling of joy and contentment.
* Freedom: The power or right to act, speak, or think as one wants without hindrances.
* Justice: Fairness and impartiality.
* Love: A strong feeling of affection and care for another person.
* Peace: A state of tranquility or quiet.
* Truth: The quality of being true or factual.
* Beauty: The quality of being pleasing to the senses or mind.
* Knowledge: Facts, information, and skills acquired through experience or education.
* Hope: A feeling of expectation and desire for a particular thing to happen.
* Faith: Complete trust or confidence in someone or something.
Philosophical Concepts:
* Existentialism: A philosophy that emphasizes individual existence, freedom, and responsibility.
* Nihilism: The belief that life is meaningless.
* Determinism: The doctrine that all events are predetermined.
* Rationalism: The belief that reason is the primary source of knowledge.
* Empiricism: The belief that knowledge comes from experience.
Social and Political Concepts:
* Democracy: A system of government where supreme power is vested in the people and exercised by them directly or indirectly through a system of representation.
* Capitalism: An economic system characterized by private ownership of the means of production.
* Communism: A political and economic ideology that promotes the establishment of a classless, stateless society based on common ownership of the means of production.
* Equality: The state of being equal, especially in status, rights, and opportunities.
* Progress: Forward or onward movement toward a destination.
Other:
* Creativity: The ability to generate new ideas and solutions.
* Innovation: The introduction of something new.
* Motivation: The reason or reasons for acting or behaving in a particular way.
* Strategy: A plan of action designed to achieve a long-term or overall aim.
* Theory: A supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
These are just a few examples, and there are many other idea nouns that could be listed.
Note: Idea nouns are often abstract and difficult to define concretely. They can be complex and nuanced, and their meanings can vary depending on context.