A person who does not wish to be in a relationship. They value their independence and do not feel they need to have a boyfriend / girlfriend / husband / wife to gain validation. People who are single by choice may still go out or date casually, but do not chose to be in a long term committed relationship.
Not to be confused with playas, pimps, hoes, etc, who stay out of committed relationships in order to justify their promiscuity.
People who are single by choice may also be so because their friends, family, society, etc, would frown upon, discriminate, or persecute them because of the relationship they are in. For example, same-sex couples, mixed race couples, etc may say that they are "single by choice" when in fact they are in a relationship, but do not wish to acknowledge that they are to people who may be hostile.
1. Mark is single by choice. He dates sometimes but values his independence too much to get involved long-term.
2. Erin is a successful businesswoman who wants the freedom to have a carreer, travel, and make her own choices in life. Therefore she is single by choice.
2. Jessica must live in her own apartment and tell her racist family that she is single by choice, because they would not approve of her black boyfriend.