If you write freelance in English, it will be "freelance".
Translated literally, "Free" means "free" and "Lance" means "spear."
The etymology dates back to the Middle Ages of Europe.
Medieval European kings and aristocrats had a culture of contracting with mercenaries every time a war broke out.
Among the soldiers, those who contracted as individuals and faced the battlefield without belonging to the mercenary corps began to appear, and they became known as "free lancers".
As a synonym for "freelance," there is the word "sole proprietorship," so I will explain it as well.