Dreamer (noun)

1. A person who dreams, especially one who has interesting or vivid dreams.
2. A person who is impractical and unrealistic and indulges in fanciful plans and ideas.

Origin:

Middle english: from old english dreamer, from dream (verb).

Examples:

1. He was known as a dreamer because of the vivid dreams he had.
2. She was a dreamer who always had her head in the clouds.
3. The dreamer had a habit of talking about his dreams.
4. The dreamer's ideas were considered too unrealistic to put into practice.
5. The dreamer's plans were often too impractical to be executed.