Solipsism (noun)

1. The theory or belief that only one's own mind can be known to exist.
2. The theory that only the self can be known or verified, and the external world is uncertain.

Origin:

The word "solipsism" is thought to be derived from the latin "solus" meaning "alone" and "ipse" meaning "self". it was coined by the philosopher and mathematician rené descartes in the late 16th century. .

Examples:

1. His solipsism made it hard for him to trust anyone.
2. Her solipsism made it hard for her to relate to others.
3. He was accused of solipsism because he only trusted his own thoughts.
4. The philosopher's solipsism was criticized by his peers.
5. The solipsism of the writer's work made it hard to connect with the characters.