A fine was a fee levied by a government as a punishment for committing a crime. It was designed to deprive a convicted party of their money as a consequence for the criminal act. This was usually reserved for relatively minor crimes.
The Ferengi Commerce Authority was empowered to levy severe fines to Ferengi found to be withholding any financial records or information from its liquidators after a writ of accountability had been issued. (DS9: "Family Business")
Quark paid a fine levied against his cousin Gaila in 2374, after Gaila was arrested on Thalos VI for vagrancy. He did so in order to recruit Gaila in his mission to rescue his mother Ishka from the Dominion. (DS9: "The Magnificent Ferengi")