Wha are the nouns that describe a person called? They are like a noun that describe's a person's perosnality, such as perfectionist, troublemaker, bookworm etc.

Traits or characteristics?

Remember that nouns don't really describe; adjectives are used to describe nouns. You're referring to nouns that indicate a person's character:
http://dictionary.reference.com/browse/characteristic

The nouns that describe a person's personality traits are often referred to as "personality nouns" or "descriptor nouns." These nouns are used to describe specific qualities or characteristics of a person. Here are some common examples:

1. Perfectionist: A person who is extremely attentive to detail and strives for perfection in everything they do.
2. Troublemaker: A person who tends to cause disruption or problems in social or professional settings.
3. Bookworm: A person who loves reading and spends a significant amount of time engrossed in books.
4. Optimist: A person who has a positive outlook on life and tends to see the good in every situation.
5. Introvert: A person who is more focused on their internal thoughts and feelings and tends to avoid large social gatherings.
6. Extrovert: A person who gains energy from interacting with others and enjoys being in social situations.
7. Ambitious: A person who has a strong desire to achieve success or reach their goals.
8. Creative: A person who possesses imaginative or original thinking and is often involved in artistic or inventive pursuits.
9. Empathetic: A person who is understanding and sensitive towards the feelings and experiences of others.
10. Adventurous: A person who enjoys taking risks and experiencing new and exciting things.

To find more personality nouns, you can make a list of personality traits and search for synonym lists or conduct searches with specific qualities in mind.